Plant Disease

Wheat Stands Good; Begin Scouting For Crown Rot................. 13

Pre-Plant Testing For Corn Nematode May Help................. 14

Catch Diplodia Tip Blight Early................. 15

Insect Science

Pounce and Ambush Approved Cutworms................. 15

Charts Aid in Determining Response to Alfalfa Weevils................. 16

Weed Science

Weed Control Essential To Successful No-Till................. 17

Compare Components In Combination Herbicides................. 17

Table: Components in Individual Herbicides................. 18

For Your Information................. 14

Weed Science

Accent and Counter 20CR-

The Story Continues To Change

Manage Weeds with Prescribed Burns……………….2

Weed Tour Set……………….2

Plant Disease

Select Quality Seed to Avoid Later Problems……………….3

Seed Treatments Offer Some Security……………….4

Consider Metalaxyl for Treating Soil, Alfalfa Seed……………….4

Insect Science

Tribute To Robert Roselle……………….5

Still Early For Sampling Weevils……………….5

Quality Samples Ensure Better Diagnosis……………….6

Environmental Programs

Pesticides: Risk Varies With Entry Routes……………….5

For Your Information……………….3

Insect Science

Army Cutworks Move into Nebraska........1

Cooperators Sought for Biological Control Program............2

Use Degree Days: Predict Alfalfa Weevil Progress..................3

Correction..................3

Weed Science

Plan Alfalfa Weed Control Before Green Up..................4

Scout Wheat Now; Begin Weed Attack..................4

Plant Disease

Examine Trees, Turf for Desiccation Injury..................5

Fewer Fungicides Available for Home Use..................5

Learn at Home with Plant Disease Slide/Tape Sets..................6

Miscellaneous

Resources..................2

New Newsletter Addresses Turf/Horticulture..................6

Pesticides: Natural Ones as Toxic as the Synthetics..................6

Weed Science

Accent/Beacon Use Poses Interaction Question .....................155

Weed Science Annual Index ....................156

Season Closes for IPW Newsletter ....................156

Insect Science

Deadline Monday for CPMU Preregistrations ....................157

Growers Surveyed about Chinch Bugs.................... 157

Insect Science (Con't)

Manual, Videotapes Teach Scouting, IPM Methods ....................157

Insect Science Annual Index ...................... 158

Plant Disease

Plant Disease Annual Index ....................159

Miscellaneous Index....................160

Plant Disease

Fall Pine Needle Drop Often Normal ......................149

Begin Control of Stripe Smut of Turfgrass ......................149

Protect High Value Turf Against Snow Mold Injury ......................150

Use Fall Spraying to Avoid Disease Problems ......................150

Insect Science

Fall Invaders Irritating, But Problem Short-lived ......................150

1991 Winter Meetings

Crop Pest Management Update ......................151

Crop Protection Clinics ......................151

Regional Weed Science Meeting ......................151

Recertification, Commercial Pesticide Applicator ......................152

Conservation Tillage Programs ......................152

Irrigation Shortcourse ......................153

Horticulture Conference ......................153

For More Information ......................153

Plant Disease

Scout Fields Now to Assess Stalk Rot Damage ........ 141

Wheat Fungicide Trial Examines Effect on Rust ...... 142

Turfgrass Rusts Severe This Fall .............................. 142

Get Out the Rakes to Reduce Disease Threat .......... 143

Weed Science

Control Turf Weeds with Fall Treatments .............. 143

Don't Wait Too Long to Attack Weeds in Alfalfa .. 144

Fall Control Program Best for Perennials ................ 144

Begin Treating Musk Thistle Now.......................... 144

Agricultural Engineering

Drying Times When Using Natural Air Drying .......... 145

Insect Science

1990 Corn Rootworm Insecticide Evaluations ............ 146

For More Information ................................................ 146

Plan for Control of Lacebugs and Psyllids .................. 147

Environmental Programs

Pesticide Development Costs Millions ...................... 147

Dates Set for 1991 Pesticide Certification .................. 148

Insect Science

Furadan Use Expanded for Wheat ...................... 135

Observe Preharavest Interval after Insecticide Use...................... 136

Treat Fleas Inside and Outside Your Home ...................... 136

Plans Being Finalized for Crop Pest Update ...................... 137

For More Information ...................... 137

Plant Disease

Be Alert to Threat of Fall Alfalfa Disease ...................... 137

Sooty Molds on trees, Shrubs is Harmless ...................... 138

Agricultural Engineering

Limit Harvest Moisture with Natural Air Drying ...................... 138

Natural Air Drying: How it Works ...................... 139

IPW Survey

We Want to Know Your Opinion.................131

Insect Science

Consider Early Harvest to Limit Com Borer Damage.......................... 131

Watch for Late Season Soybean Insects.......................... 132

Biological Systems Engineering

Clean, Prepare Bins for Harvest.......................... 132

Plant Disease

Stalk Rot Can be Serious; Scout Fields Now.......................... 132

Sorghum Leaf Spots Now Prevalent.......................... 133

Powdery Mildew Common; Treat with Fungicides.......................... 133

Irrigate Young Trees to Avoid Losses.......................... 134

Insect Science

Russian Wheat Aphids Hit Hard in the Panhandle ................................. 125

Begin Scouting Sorghum Fields for Greenbugs .............................. 126

Get the Buzz on African Bees .............................. 126

Plan Now to Reduce Chinch Bugs in 1991 .............................. 127

Weed Science

Stop Leafy Spurge Advance with Fall Treatn1ent .............................. 128

2,4-D Helpful for Controlling Hemp Dogbane .............................. 129

Plant Disease

Improve Lawn to Reduce Disease Potential .............................. 129

Slime Molds Pose Little Threat to Grass, Gardens .............................. 129

Anthracnose Causing Problems for Cucumbers, Melons .............................. 130

For More Information .............................. 130

Plant Disease

Wheat Disease Management Begins Before Planting ................................................ 121

Accurate Tree Descriptions Improve Diagnoses ........................................... 122

Insect Science

Youths: Don't Get Bored, Get Bugged .................... 123

Cultural Practices are Best Means for Hessian Fly Control This Fall .......................... 123

Caputre 2EC Use Continued until Sept 15 .............. 124

Whitefly Control Difficult in Gardens ...................... 124

Insect Science

Corn Leaf Aphids Found Abundant in Some Fields .............. 115

Use Guides to Determine Defoliation Levels .............. 116

It's Time to Scout for Mexican Bean Beetles, Western Bean Cutworms .............. 117

EPA Cancels Capture Exemption .............. 118

For More Information .............. 118

Plant Disease

Manage Alfalfa Stands for Longevity .............. 118

How to Identify Soybean Cyst Nematode Damage .............. 119

Environmental Programs

Pesticides and Farm Sales May Not Mix .............. 119

Insect Science

Capture 2EC Gets Crisis Exemption .......................... 109

European Com Borers: To Treat or Not to Treat Worksheet Aids in Determination .......................... 110

Worksheet .......................... 110

Com Rootworm Beetle Numbers High .......................... 112

Take Steps to Protect Honeybees from Pesticides .......................... 111

Attack White Grubs in Turf in Early August .......................... 111

Agricultural Meteorology

Use Degree Days to Predict Pest, Plant Growth .......................... 112

Plant Disease

Don't Eat the Mushrooms .......................... 113

Pack Samples Carefully for Accurate Diagnosis .......................... 113

Check Them Out .......................... 113

Rust-Colored Turf Signals Disease .......................... 114

Insect Science

European Corn Borers Emerging, Laying Eggs ................... 103

How to Determine Need for Grasshopper Control................... 104

Try Cleaning, Treatment to Eliminate Fleas ................... 104

Crop Pest Update Scheduled ................... 105

Spider Mites Sighted in Western Half of State ................... 105

For More Information ................... 105

Plant Disease

Scout Now for Signs of Foliar Diseases ................... 106

Be Alert to Anthracnose in Established Alfalfa Stands ................... 107

Maize Chlorotic Mottle Virus Reported ................... 107

Weed Science

Begin Bindweed Control With Fall Treatment ................... 107

Herbicide Guide Revised ................... 107

Plan Now for Late Season Weed Control ................... 108

Include Turf Renovation in Fall Yard Work ................... 108

Insect Science

Begin Scouting for Com Rootworm Beetles ...... 97

Watch for Western Bean Cutworm Eggs ............ 98

Control Volunteer Wheat to Reduce Pests.......... 98

Potatoes Subject to a Variety of Pests ................ 99

Potato Leafhoppers Attacking Alfalfa .............. 99

Mimosa Webworm Damage Mostly Aesthetic……………….. 99

Stable Flies a Major Nuisance This Year .......... 100

Environmental Programs

Study Finds Little Leaching of Lawn Care Chemicals .................................................... 100

Plant Disease

Hot Weather Leading To Turf Problems .................. 101

Ash Decline a Mystery; But Homeowners Can Aid Recovery ........................................................ 101

For More Information ............................ 102

Weed Science

Rescue Treatments for Soybeans ...................... 91

Timing Vital to Late Season 2,4-D Use ...................... 92

Spray Winter Wheat Stubble 5-30 Days After Harvest ...................... 92

Correction ...................... 92

Attack Weeds Directly with Wipers, Bean Bars ...................... 93

Insect Science

Turfgrass Field Day, Equipment Show July 24 ...................... 93

Baythroid 2 Exemption Continued ...................... 94

Don't Let Flies Ruin County Fair Festivities ...................... 94

Gardeners Beware: . Hoppers Invited To Lunch ...................... 94

Fall Webworms Not Harmful ...................... 94

Plant Disease

Barley Yellow Dwarf Analyzed in 11 Oat Cultivars ...................... 95

Phythophthora Root Rot Identified in Soybean Samples ...................... 95

Not All Yellow Turf is Diseased ...................... 95

Plant Disease Clinic Services Reduced for One Week ...................... 95

Leaf Spots Threaten Tomatoes ...................... 96

Environmental Programs

National Ground Water Survey Taken ...................... 96

Plant Disease

Wheat Leaf Rust Causing Early Flag Leaf Loss .................... 85

Wheat Scab Discovered in South Central Nebraska .................... 85

After the Recent Storms: Forecast Ideal for Diseases In Corn: Holcus Spot and Goss's Wilt, Blight .................... 86

In Soybeans: Bacterial Blight .................... 86

Barberry Shrubs Show Verticillium Wilt Symptoms .................... 87

Good Samples, Labels Essential to Diagnoses .................... 87

Weed Science

Attack Perennial Weeds at Early Flower Stage .................... 87

ACR Acres Offer Good Potential For Weed Control .................... 88

Insect Science

Chinch Bug Invasion Continues .................... 88

Tiger Mosquito May Enter State .................... 88

Potato Leafhoppers Move Into Eastern Nebraska .................... 89

Thrips Populations Developing in Dry Beans .................... 89

Banks Grass Mites Move Into Corn.................... 90

Insect Science

Baythroid 2 Gets Special Label for Sorghum........................ 79

Managing First Generation Com Borers ........................ 80

Borer Treatment Worksheet ........................ 80

Replant Options After Herbicide Use ........................ 82

Weed Science

Consider Whole Field When Choosing Herbicide........................ 81

After Applying Insecticides, Wait Before Re-entering ........................ 81

Plant Disease

Dutch Elm Disease Evident Across State ........................ 83

Wheat Rust Becoming Epidemic ........................ 83

Oats Still Show Barley Yellow Dwarf ........................ 83

New Compendium Published for Apple/Pear Diseases ........................ 83

Wheat Dying Prematurely ........................ 84

For Your Information........................ 84

Plant Disease

Northeast Nebraska Oats Showing Signs of Wind Burn .................................. 73

Yellow Corn Problem Does Disappearing Act .................................. 74

Remove Turfgrass Plugs Carefully for Diagnoses .................................. 74

Heavy Leaf Loss in Trees May Not Be Serious .................................. 75

Brown Patch Found in Turf .................................. 75

Weed Science

Tackle Weeds in Soybeans Postemergence .................................. 76

Heavy Rains Aid Weeds as Well as Grasses .................................. 76

Insect Science

Corn Rootworms Best Controlled at Cultivation.................................. 76

Chinch Bugs Invade Sorghum Not Near Wheat .................................. 77

European Corn Borers Emerging .................................. 77

Scout Alfalfa Fields After Harvest for Weevils .................................. 78

Watch for Armyworms in Wheat .................................. 78

For More Information .................................. 77

Insect Science

Bean Leaf Beetles Move to Early Soybeans .............65

Species Identification Important to Aphid Control.............66

Status of Pesticides Clarified .............66

Clean Equipment Key to Quality Grain Storage .............67

Watch for Aphids Attacking Ornamentals ............... 67

Floating Row Covers Exclude Many Garden Pests ... ....................... 68

Plant Disease

Recent Wet Weather May Increase Wheat Diseases .............68

When Should You Replant Com After Floods? .............69

Anthracnose Disease Attacking Sycamores .............. 69

Diagnosis, Control Important to Managing Pine Wilt .............70

Watch for Turf Disease Problems .............70

Weed Science

Producers Warned: Pursuit Use illegal on Com .............70

Annual Weed Tour June 19-21 .............70

Some Herbicides Offer Delayed Application .............71

Avoid Herbicide Problems During Cool, Wet Weather .............72

For More Information.............67

Weed Science

Take Precautions to Limit Herbicide Drift...................................... 59

Options Suggested for Postemergence Weed Conttol...................................... 60

Plant Disease

Foliar Disease Pressure Increasing on Wheat...................................... 60

Diagnostic Clinic Accepting Plant Disease Samples...................................... 61

Fungicides To Conttol Strawberry Gray Mold...................................... 61

Insect Science

How to Decide When to Treat Alfalfa Pests...................................... 62

Repellent May Cause Rare Problems...................................... 62

Limit Tick Exposure, Potential for Disease...................................... 63

Get the Facts on Lyme Disease...................................... 63

Correction to Insect Guide ............................................ 64

We'll Be Back ...................................... 64

For More Information...................................... 61

Plant Disease

Foliar Disease Pressure Increasing on Wheat ..............51

Examine Seeds to Determine Type of Grain Damage ..............52

Fungi Strikes Iris Early ..............52

Oak Wilt a Possible Threat in Nebraska.............. 52

Insect Science

Clover Leaf Weevil Common in Alfalfa ..............53

Pest Update: Chinch Bugs Active ..............54

Treatment Depends on Type of Cutworm ..............55

Black Cutworm Movement Causes Concern ..............56

Take Heart: Protect Man's Best Friend ..............56

Eliminate Water to Eliminate Mosquitoes ..............57

Weed Science

Beacon Receives Federal Registration ..............57

Rotary Hoe Can Be an Economical Method of Weed Control ..............58

For Your Information ..............54

Plant Disease

Cut Alfalfa Early For Lead Disease Control................45

Seedling Sugar Beets Hit By Diseases, Freezing Injury................45

Bacterial Wetwood, Slime Flux Caused By Bacterial Activity................46

Fungal Disease May Cause Premature Needle Drop................46

Weed Science

Control Options Limited For Postemergence Shattercane................47

Stop Leafy Spurge Now Before It Spread................47

Weed Scientist Joins Scottsbluff Staff................48

Insect Science

Crop Pest Update: Weevils On The Move................48

Control Tree, Shrub Pests With Immediate Treatment................48

Bed Bugs, Bat Bugs, And Bird Bugs- Avoiding Their Bites................49

Use of Temik On Potatoes Halted................49

New Insecticides Listed For Termite Control................50

For Your Information................49

Insect Science

Russian Wheat Aphid Problem Excalates ................ 37

Use Extended for Lorsban 4E on Russian Wheat Aphid ........................................................ 38

Chinch Bugs Invade Wheat in Southeast Nebraska .............................................................. 38

For More Information .............................................. 38

Chinch Bug Control Requires Early Planning .......... 39

Baythroid Proposed for Control .............................. 39

Label Changed on Force 1.5G Insecticide ................ 40

Update: Alfalfa, Clover Leaf Weevils Moving In ........................................................... 40

Watch for Army Cutworms in Western Nebraska .............................................................. 41

Plant Disease

Wheat Leaf Rust Severe in Arkansas, Texas .......... 41

Powdery Mildew Now in Wheat ............................ 41

Stripe Smut Active in Turfgrass ............................ 41

Soybean Seed Treatment: Yes or No? .................... 42

Apply Fungicides to Control Dothistroma Needle Blight.............42

Padded Mailers Available ...................................... 42

Weed Science

New Herbicides Approved for Dry Edible Beans.... 43

Triazine-resistant Kochia Requires Special Plan .... 43

Passport Registered ................................................ 44

Plant Disease

Atrazine Contaminated Benlate Recalled by Manufacturer ................................................ 31

Cedar Apple Rust Galls Appear as Bright ()range Growths ........................................ 32

Scout Alfalfa for Spring Blackstem .......................... 32

For More Information. ................................................ 32

Insect Science

Grasshopper Return Warned Crop Pest Update ........................................................ 33

Bluegrass Billbugs Hide Below Surface; Destroy Turf Roots ............................................... 33

New Publications Describe Substitutes for Synthetic Insecticides ....................................... 34

Spring Temperatures Initiate Elm Leaf Beetle Activity in Homes.................................................. 34

Environmental Programs

Diazinon 14% Granular Gets Restricted Use Label... .. 34

Weed Science

Combine Chemical and Biological Methods for Musk Thistle Control. ........................................ 35

Buctril Registered for Seedling Alfalfa ....................... 36

Weed Science

Where Do the New Shattercane Herbicides Fit In?...................................... 25

Start Thistle Control Now ............................................ 26

Schedule Set for 1990 Weeds Tour ............................. 26

Plant Disease

Disease Update: Soilborne Wheat Mosaic Found ...... 27

Evergreens Showing Signs of Winter Desiccation ...... 27

Send Fresh Samples for Disease Testing ..................... 28

New Publications Announced ........................................... 28

Insect Science

Watch for White Grubs During Planting ...................... 28

Correction ................................................................. 29

Alfalfa Weevils Entering Eastern Nebraska ................ 29

Black Cutwonn Tiapping Program
Helps Predict Moth Migration .................................. 30

Insect

Lorsban Given Emergency Registration for Wheat .......................................................... 19

Search is On For C-7 Lady Beetle .......................... 20

Crop Pest Update: Alfalfa, Clover Leaf Weevils Found .................................................. 20

Beekeepers Field Day Set for May 5 ...................... 20

Start Watching for Grape Flea Beetle .................... 20

For More Information ................................................ 20

Weed Science

Combination Herbicides -What's in a Name? ...... 21

Herbicides Labeled for Postemergence Weed Control on CRP Acres .............................. 22

Plant Disease

Apply Fungicides to Control Diplodia Tip Blight of Pines .................... ......... 22

Wheat Disease Update: Few New Problems Developing ............................... 23

Protect Against Phytophthora Root Rot ................ 23

Treat Iron Chlorosis of Trees and Shrubs in Early Spring ............................ 23

Plant Disease Slide Sets Produced ........................ 23

Lawn Fungi Problems Not Quite So Magical as the Myths ..................... 24

Weed Science

Herbicide Label Changes Outlined ........................... 13

Early Weed COlltrol Important to Maintaining Healthy Turf ............................. 14

NebGuide Explains Process for Submitting Pest/Plant Samples ............................................ 14

Plant Disease

Soilborne Wheat Mosaic Symptoms Now Evident in Eastern Nebraska ...................... 15

Tomato Spotted Wilt Virus Attacks a Wide Range of Plants .................................... 15

It's Time for Garden Clean-up ................................. 15

Prune to Eliminate Black Knot ............................... .16

Dethatch and Aerify Lawn for Thatch Management Program .................... 16

Insect

Thrips Damage Horticultural Plantings .................... 16

Treatment Recommendations Changed .................... 17

Chinch Bug Migration Beginning ............................. 17

Panhandle Insect Problems Developing .................... 18

Correction ....................................................................... 18

Plant Disease

Avoid Heavy Fertilizing in Early Spring to Prevent Lawn Diseases ................................... 7

Multi-resistant Alfalfa Offers Security from Diseases ........................................ 8

Plan Plantings to Avoid Cedar Apple Rust .............. 8

Avoiding Salt? Do the Same for Your Plant. .......... 8

Insects

Com Rootwonn Control Starts with Careful Planning ......................................... 9

Examine Trees Now for InsectEggs ....................... 9

Anny Cutwonns Advance Into Dawson County ......................................... 10

Pest Scouting Guides Available ............................. 10

Inspection, Treatment Keys to Houseplant Pest Control.. ....................... 10

When Carpenter Ants Come Marching, Protect Your Home ........................................... 11

Weed Science

Early Application the Key to No-till Weed ControL ...........................11

To Our Readers .................................................... 1

Insects

Chinch Bug Outlook ............................................. 2

Chinch Bug Survey Results .................................. 2

Early Spring Control of Cankerworm and Iris Borer ................................................... 3

Dormant Oil Sprays.................................................3

Clover Mites Getting Active........................................3

CPMU Proceedings Available .............................. 3

Plant Disease

Check Alfalfa Early for Winterkill, Disease........ .4

Winter Wheat Growers: Be Alert to Crown and Root Rot. ....................................... .4

The EBDC Situation............................................ .4

Non-Chemical Disease Control.............................. 5

Weed Science

Weed Control in Winter Wheat. ................................ .5

Beware of Miracle Herbicides .............................. 5

Alfalfa Weed Control .......................................... 6

Weed Control in Oats ........................................... 6

• 1990 Crop Protection Clinic Schedule
• It's Not Too Late
• Control Alfalfa Now - No-Till in '90

1990 Crop Protection Clinic Schedule

The dates and locations for the 1990 Crop Protection Clinics have been set. As in the past, we will continue the format of 15-minute presentations with time for questions. Entomologists, Plant Pathologists, and Weed Scientists will be presenting the latest information. Commercial applicators are reminded that the 1990 clinics will be used to re-certify applicators in several categories. More details on the clinics will be available in our November newsletter.

It's Not Too Late

A relatively hard freeze need not shut down weed control activities. A lot of our tough weeds thrive when temperatures are in the 40's and 50's in mid to late fall. Here are some weed control operations that can be done during the next four to six weeks, weather permitting:

--Make herbicide applications for pennycress and downy brome control in established alfalfa. Karmex, Sencor/Lexone, and Sinbar should be applied to dormant alfalfa.

Control Alfalfa Now - No-Till in '90

Eventually alfalfa stands become unproductive and the land must be rotated to another crop. Plowing is an expensive and sometimes not completely effective way of killing alfalfa. Killing the alfalfa with herbicides is more economical than plowing, is very effective, and leaves the soil less subject to erosion. An economical, consistent alfalfa control treatment is a combination of 1 qt. 2,4- D (4 lb./gal) + 0.5 pt. Banvel per acre. The herbicide approach will cost $6.00/A + application cost compared with $10.00-$15.00/A for plowing.

• Husk Thistle Control
• Field Bindweed and Other Perennials
• Fall Weed Control in Alfalfa--Don't wait Too Long
• Fall Lawn Weed Control

Musk Thistle Control

October and early November are excellent times to control musk thistle providing the weather cooperates. A good fall control program normally eliminates the need for spring control. This is because plants that would flower next summer are normally growing in the fall. However, the success of a fall control program depends on adequate fall rainfall. Dry weather reduces musk thistle seed germination and plant establishment. Where the weather has been dry, there may be no plants to control. Examine the site and determine if the thistle population justifies spraying. Herbicides and per acre rates to use on musk thistle are Tordon ·22K at 6 to 8 fluid ounces, 2,4-D + Banvel at 1.0 lb + 0.5 pt, and 2,4-0 at 1.5 to 2.0 lb. These treatments are ranked in order of effectiveness for fall application. When mild, moist conditions prevail, all three treatments are effective. Under very dry, cool conditions only Tordon can be expected to perform well. Treatments should be applied after October 1.

Field Bindweed and Other Perennials

Perennial weeds including field bindweed, Canada thistle, and others can be effectively treated with herbicides in the fall. Food storage in the root system of these plants is taking place in the fall. Herbicides applied at this time to plants with excellent top growth readily move down to the roots along with the food. In the fall, temperatures and soil moisture are generally more favorable for plant growth than during the summer, a condition required for best herbicide performance.

Fall Weed Control in Alfalfa--Don't wait Too Long

Fall is an excellent time to control weeds in established alfalfa. Fields that were weedy this year will almost certainly be weedy again next year unless preventative measures are taken. Many times the problem is not recognized until the alfalfa "greens up" in the spring--then it is too late for most herbicides. This year get a "jump" on the problem.

• Fall Seeded Crops and Herbicide Residues in the Soil

Fall Seeded Crops and Herbicide Residues in the Soil

Herbicide applications made to corn, sorghum, and soybeans must be reckoned with where alfalfa or winter wheat is being considered for fall planting on drought stricken fields.

The guidelines that follow come from labels, product literature, research, and experience. They have been established to protect the user and manufacturer and contain safety factors for average growing conditions. Drier than normal June, July and August weather has undoubtedly prolonged soil longevity of some products.

We have chosen to discuss herbicides that may present a problem. Herbicides not discussed are expected to present no problem. Discussions below are for each individual herbicide. Where combinations have been used, the most phytotoxic material should be used to determine the planting decision.

• Late Season Weed Control in Corn and Sorghum
• Bindweed Control Where Wheat is to be Planted
• August Lawn Renovation
• Herbicide Use Guide Revision

Late Season Weed Control in Corn and Sorghum

Late season broadleaf weed control in corn and sorghum is possible with 2,4-D. Such a treatment could make harvesting easier and reduce weed seed production. Treatments should be applied no later than flowering stage of weeds for control of seed production. Both corn and sorghum can suffer yield reductions from 2,4-D applied during the flowering period. As a guideline, 2,4-D use on corn can be resumed after the silk turns brown. The use of 2,4-D on sorghum can be resumed after the grain reaches the early dough stage. Sorghum should not be sprayed with 2,4-D between the beginning of head emergence and the milk stage of the grain. These late 2,4-D treatments will not cause lodging or stalk brittleness in the crop.

Bindweed Control Where Wheat is to be Planted

Fall is usually an excellent time to make herbicide applications for field bindweed control. However, healthy new growth on the bindweed is essential for good results. Avoid tillage for at least 30 days prior to treatment. Dry weather in some areas has reduced bindweed growth making it more difficult to control. It would be best to wait for rain and new bindweed growth before treating. This could be too late this fall for land going to wheat. September treatments are usually more effective than August treatments.

August Lawn Renovation

August is the time to get started with turf renovation. Roundup is a useful herbicide for such projects. Skip one or two mowings so there is good growth on the weeds and grass for herbicide intake and activity. Apply 2 1/2 to 3 oz. of Roundup/1000 sq. ft. using 1 gal or less of water. Delay vertical mowing, slicing, coring, and power raking for seven days.

Herbicide Use Guide Revision

Industry reps, extension agents, and all other users of our Herbicide Use Guide: now is the time to submit your suggestions for our 1990 edition. We appreciate your input of previous years. You have helped make the Nebraska Herbicide Use Guide a most useful weed control aid for farmers, dealers, applicators, farm managers, consultants, extension agents, and others.

• Late Season Broadleaf Weed Control in Corn and Sorghum
• Rescue Treatments for Soybeans
• Wiper and Bean Bar Applications
• Nebraska Leafy Spurge Conference

Late Season Broadleaf Weed Control in Corn and Sorghum

Corn should not be sprayed with 2,4-D from a week before tassel emergence until after the silks turn brown. Treatments during this critical time often interfere with pollination and cause yield reductions. After the silks turn brown, pollination is complete and 2,4-D use can safely resume. The early planted corn in Nebraska is now in the stage where it should not be sprayed with 2,4-D.

Rescue Treatments for Soybeans

Most broadleaf weeds taller than 6" cannot be consistently controlled in soybeans with postemergence herbicides. There are no soybean herbicides that perform like 2,4-D and Banvel.

Wiper and Bean Bar Applications

Wiper applicators are popular for controlling tall growing weeds in shorter crops. The weeds should be at least. 10" taller than the crop. Roundup is the herbicide of choice for wiper applications in sorghum and soybeans. A concentration of 25% Roundup in water is used for control of broadleaf and grass weeds. Shattercane and volunteer corn are very susceptible to Roundup. Roundup concentrations of 20% work well on these plants.

Nebraska Leafy Spurge Conference

• Control Weeds on ACR Acres
• New Registrations

Control Weeds on ACR Acres

Left unattended, ACR acres can turn into a real weed problem next year. Take advantage of the opportunity to clean up a weed problem; don't create a problem for next year.

Ideal growing conditions coupled with no tillage on ACR acres have set the stage for excellent control of perennial weeds. Keys to success in perennial weed control with herbicides are good growing conditions and correct growth stage of the weed.

New Registrations

Gallery 75df from Elanco has received federal registration. Gallery is a pre emergence broadleaf herbicide for use in turf and ornamentals. Fall or early spring applications will control 44 different broadleaf weeds including knotweed, oxalis, spurge, plaintain, henbit, white clover, and chickweed.

Poast from BASF has been granted a section 18 registration for postemergence grass control in fieldbeans. Poast can be applied by ground or air using crop oil concentrate as an additive. A single or two applications can be made at a rate not to exceed a total of 1 pt/A. Users need to complete a permit available from the Nebraska Department of Agriculture. For information from the Department of Agriculture, contact Rich Reiman, 402/471-2394.

• Postemergence Weed Control in Grain Sorghum
• Small Grain Harvest Aid
• Pasture and Range Weed Control
• Lawn Weed Control

Postemergence Weed Control in Grain Sorghum

Crop growth stage restrictions are an important consideration when choosing a postemergence herbicide for use in sorghum. This year's uneven stands complicate the situation further. Our advice is to gauge treatments based on how the majority of the field develops. Earlier applications may allow lower rates, better coverage, and more effective weed control. Do not cultivate for 5 days prior to or after a herbicide application.

Small Grain Harvest Aid

Thin stands coupled with the recent rains may lead to excessive weed growth in ripening small grains. Broadleaf weeds, especially, can cause serious harvesting problems. 2,4-D ester at 1 quart per acre (4 lbs. per gallon material) will knock down and dry up most broadleaf weeds. No tall brands of 2, 4-D are labeled for this use. Applications made after the hard dough stage of the grain will not affect grain yield. By waiting until the green color is gone from the nodes -(joints), stem brittleness and breakage can be avoided. It usually takes 7-10 days for the 2,4-D to knock down and dry up the weeds.

Pasture and Range Weed Control

Normally, the later part of June is the best time to treat broom snakeweed, vervain, goldenrod, sagebrush, snow-on-the-mountain, and western ragweed. There is a tendency to treat on the late side rather than too early. A good guideline for treating most perennials is to mow or apply the herbicide when the weeds are in the early flower bud stage. Biennial thistles are an exception and should be treated in the rosette stage.

Lawn Weed Control

Summer months are not the time to apply herbicides for perennial broadleaf weed control in turf. Dry, hot weather reduces the effectiveness of most postemergence herbicides and control suffers. wait until late September to early October to control perennial broadleaf weed problems. In addition to lack of control, high temperatures and wind speed increase the chances of drift and volatility problems which will cause injury to sensitive plants. This is especially true for materials that contain dicamba (Banvel), but 2,4-D and MCPP (mecoprop) can also cause drift injury.

• Postemergence Weed Control in Soybeans
• Do Not Use Pursuit on Corn
• Weed Tour Reminder

Postemergence Weed Control in Soybeans

Weeds in soybeans planted during the last ten days of May are reaching the stage when they should be controlled. Weeds between the rows can be controlled with a cultivator but weeds within the row are best controlled with herbicides. Success with postemergence herbicides hinges on timing of the application.

Do Not Use Pursuit on Corn

We are aware that some growers are considering using Pursuit postemergence for shattercane control 1n corn. Pursuit is registered for use in soybeans but is not approved for use in corn. The use of Pursuit in corn would result in illegal pesticide residues in the corn and subject the crop to condemnation. Grain not only from the treated crop but all grain stored with it would be subject to condemnation. The applicator would be subject to penalties for violating the pesticide label. Research conducted by Dr. Fred Roeth shows that treating corn with Pursuit postemergence results in a yield reduction of 30-50% even if no weeds are present. We and American Cyanamid strongly discourage the use of Pursuit or any other pesticide in a manner other than specified on the label.

Weed Tour Reminder

The Nebraska Weed Tour is scheduled for June 20 at Scottsbluff and North Platte. The tour continues at Clay Center and Lincoln on June 21 and concludes at Concord on June 22. Details on the itinerary were listed in our May 9th Newsletter.

• Postemergence Weed Control in Corn
• Herbicide Drift

Postemergence Weed Control in Corn

Ory weather has reduced herbicide performance, resulting in poor weed control in some early planted corn. To control escaped grasses, atrazine with oil should be applied when the grass is less than 1 ½” tall. Bladex 80W, 90DF or Extrazine II can also be used but don't apply with oil or if the corn is past the 4-leaf stage. Tandem in combination with either Bladex or atrazine increases postemergence activity. If atrazine has already been used as a soil application, be aware of, potential carryover problems from an additional postemergence treatment. If Bladex has already been used as a soil application, do not exceed the maximum labeled rate for your soil type. Prowl plus atrazine (Prozine) or Prowl + Bladex can be applied up to the 4-leaf stage of corn.

Herbicide Drift

Herbicide injury problems from drift and volatility occur each year. Farm crops as well as gardens, ornamentals and windbreaks are damaged. This not only applies to farm chemicals, but turfgrass herbicides as well.

• When and How to Rotary Hoe
• Turfgrass Research Field Day
• Reclassification of Bromoxynil
• Grass Control in Ornamentals
• Scott Nissen Joins Faculty at Lincoln

When and How to Rotary Hoe

The rotary hoe, properly used is an effective tool for weed control in row crops. Crop plants seeded 1 to 2 inches deep escape appreciable injury from a rotary hoe. For best results weed seedlings should be in the "white stage," from germination to emergence at the time of hoeing. Timeliness is critical for success because emerged green weeds, even though small, are generally too well anchored for control. A second hoeing 5-7 days after the first provides improved control. A dry firm soil surface during the hoeing operation is· required. A rain-free period of several hours after hoeing is needed to desiccate the weed seedlings. Hot windy conditions for a few hours after the operation are best. A rainy period of several days seriously reduces the effectiveness of a rotary hoe program. A rotary hoe will not satisfactorily control larger-seeded weed seedlings including shattercane and velvetleaf because they germinate deeper in the soil and are more firmly anchored than small-seeded weeds such as pigweed and foxtails. Operational speeds of 7-14 mph are used in rotary hoeing. Effectiveness is greater at the faster speeds; however, injury to delicate crops also increases with speed.

Turfgrass Research Field Day

The 14th Annual UNL Turfgrass Research Field Day and Equipment Show will be held Tuesday, June 20, 1989 from 8:00 a.m. to 3:00 p.m. The Field Day will be held at the John Seaton Anderson Turfgrass Research Facility, just south of the Agriculture Research and Development center headquarters located at Mead, NE.

Reclassification of Bromoxynil

Bronate, Buctril, and Buctril + Atrazine herbicides have recently been reclassified as Restricted Use Pesticides. All of these products contain bromoxynil and significant label changes have occurred. Additions include: 1) New warning statements; 2) Specific use directions requ1r1ng additional protective clothing and clean-up procedures; 3) The requirement of mechanical transfer systems when handling 30 gallons or more product in a single day; 4) Use of enclosed cabs when applying 180 or more acres in a single day; and 5) New chemigation and aerial restrictions.

• 1989 Weed Science Tour
• Summer Hours
• Buckbrush and Snowberry -- Control Time Is Now
• Yellow Nutsedge Control in Turf

1989 Weed Science Tour

The itinerary has been set for the 1989 Weed Tour. This year the tour will progress from west to east across the state. The itinerary is as follows:

Summer Hours

Our summer office hours are from 7:30 a.m. to 4:30 p.m. We are often in the field at this time of year and you may get a more immediate response by contacting the extension agent in your county.

Buckbrush and Snowberry -- Control Time Is Now

Buckbrush and western snowberry development is advanced due to early season warm temperatures. Research shows there's a brief two-week period in May during which 2,4-D performs effectively for the control of these two woody plant species. Control time is now -- May 10 to 25 in eastern and southern Nebraska. Northward, initial treatment could be delayed until May 20. Apply 1 ½ quarts of low volatile 2,4-D ester (4 lbs active ingredient per" gallon) per acre in enough water to provide good coverage.

Yellow Nutsedge Control in Turf

Yellow nutsedge is one of the most troublesome weeds in turf. The warm temperatures in April have caused yellow nutsedge to come on earlier than normal this spring. Basagran is the safest and most effective herbicide for yellow nutsedge control and is now available in pint containers. Mix ¾ to 1 ½ oz. /gal of water along with an equal amount of surfactant or detergent and apply to vigorously growing plants. This will treat 1,000 square feet. If desired control is not obtained with the first application, make additional applications at 10 to 14 day intervals. OSMA, MSMA and other methyl arsenates can also be used for control, but repeat applications at 7 to 10 day intervals are also necessary. The organic arsenicals can discolor turf and should not be applied when temperatures are above 85 degrees. With either approach, don't mow for 4 to 5 days before and after application.

• Postemergence Shattercane Control in Corn
• Algae and Moss Control in water and stock Tanks
• New Registrations

Postemergence Shattercane Control in Corn

Postemergence control of shattercane in corn is limited. Bladex 80W or 90DF used with vegetable oil or a surfactant can be used before corn exceeds the 4-leaf stage. The Bladex label does not claim shattercane control. Our observations are this treatment stunts small shattercane plants but may not kill them. Similar results may be obtained with 2 qt./A atrazine used with crop oil concentrate. Tandem used with Bladex or atrazine will improve activity. Similarly, Prowl used with Bladex or atrazine before the 5-leaf stage of corn improves activity compared to the triazine alone. While these treatments don't kill the shattercane, they set it back, allowing the corn to get ahead of the cane. This sets the stage for effective control with cultivation.

Algae and Moss Control in Water and Stock Tanks

With warmer weather, moss and algae will again make their appearance in plastic nurse tanks used to hold water supplies for spraying operations. Control is simple and inexpensive.

New Registrations

-Soybeans

Sencor can be tank-mixed with the following: Commence, Cannon, or Freedom.

Salute can be tank-mixed with the following: Scepter, Command, Commence, Squadron, or Tri-Scept.

• Leafy Spurge Control
• Pasture spraying and Grazing Restrictions
• Weather Your Herbicide Works or Not

Leafy Spurge Control

Leafy spurge, an aggressive plant, continues to spread in Nebraska, greatly reducing the carrying capacity of grazing land. The weed is more common across the northern portions of the state but can be found elsewhere. Leafy spurge is a perennial and reproduces from seed as well as from buds on its deep, extensive root system. It reduces forage production and cattle avoid grazing infested areas because it is an irritant and mildly poisonous. Because of the unusually warm temperatures this spring, the development of the plant is about two weeks ahead of schedule.

Pasture Spraying and Grazing Restrictions

Grazing restrictions on sprayed pastures vary with the herbicide and the type of livestock. with 2,4-D, do not graze animals on treated areas for 7 days after treatment. Dairy animals should not graze· treated areas for 14 days after treatment. Remove meat animals from treated areas 7 days prior to slaughter. Withdrawal is not needed if 14 days have elapsed since treatment. Do not cut treated grass for hay within 30 days of treatment.

Weather Your Herbicide Works or Not

The dry spring we've had so far may adversely affect some early preplant treatments. All pre emergence applications require rainfall to activate them, including early preplant treatments. In some situations, very little or no rainfall has occurred since these treatments were applied. This doesn't present a problem as long as the weeds haven't germinated. However, in some situations there may be enough moisture present to cause weeds to come on.

• CRP Acres - Postemergence Weed Control
• Combination Herbicides--What's In a Name?

CRP Acres - Postemergence Weed Control

Several herbicide treatments are registered for postemergence broadleaf weed control in CRP plantings including Ally, Buctril, Curtail, Glean, 2,4-D and 2,4-D + Banvel. Curtail can be used only on established grasses. The other treatments can be used on grasses from the 3-leaf stage on, except 2,4-D and 2,4-D + Banvel which must go on after the 5-leaf stage. Grasses in this juvenile stage especially warm season grasses will not tolerate the higher rates of 2,4-D and Banvel used on established grasses. Grasses germinating this spring will be injured by residues of earlier 2,4-D and Banvel applications.

Combination Herbicides--What's In a Name?

The prepackaged herbicide picture continues to change. Evaluating weed control performance, crop safety, and carryover potential of combinations compared with tank mixtures is dependent on the amount of each component in the combination. sometimes it is difficult to tell how much atrazine is contained in 3 qt. of Bicep or 3 qt. of Extrazine II. The following table lists the equivalent amount of each component contained in a gallon or pound of some combination products. The totals don't always add up to 1 gallon or 1 pound of herbicide because the combination products may be more or less concentrated than the individual herbicides.

• Lawn Weed Control
• Musk and Plumeless Thistle
• No-Till Into Alfalfa Sod
• Nebraska Weed Tour

Lawn Weed Control

Postemergence control of dandelions, shepherdspurse, chickweed, and henbit should have been done by now or should be done soon. Granular forms of 2,4-D, Trimec, and similar herbicides are safest to use under most conditions. However, Trimec and other formulations containing dicamba (BANVEL) should be used sparingly next to and under trees and shrubs. Turflon from Dow is also labeled for control of many broadleaf weeds. Liquid herbicide formulations should be applied when there is little or no wind movement and with low spray pressure. It's a good idea not to remove clippings until the lawn has been mowed at least four times because of residual herbicide concentrations. If clippings are removed, they should not be used as a mulch around trees or flower beds.

Musk and Plumeless Thistle

Check pastures and rangeland for musk and plumeless thistle. Now is the perfect time to apply herbicides for their control. Thistles are most susceptible to herbicides when they are in the rosette stage. Musk and plumeless thistle grow under cool conditions. Therefore, herbicides are slower acting but still effective. It's important to apply herbicides before the thistles bolt. It's much better to treat a thistle rosette on a 50° F day than a bolted plant on a 70° F day.

No-Till Into Alfalfa Sod

Killing alfalfa with herbicides is more economical than plowing, is very effective, and leaves the soil less subject to erOS10n. An excellent seedbed results from herbicide-killed sod whether the crop is planted no-till or following light tillage. The most consistent treatment we have evaluated for alfalfa control is 1 qt. 2,4-D + 0.5 pt. Banvell A with 2 qt 2,4-D ester/A a close second. The herbicide approach will cost $5.00-$6.00/A + application compared to $10.00-$15.00 for plowing and seedbed preparation. Alfalfa should be actively growing and have at least 4" of green growth at treatment.

Nebraska Weed Tour

Mark your calendar. The 1989 Nebraska Weed Tour will be held the week of June 19. We will be viewing Weed Science research across the state during this tour. Details will be provided in a later newsletter.

• Correction
• No-Till Weed Control
• Weed Control in New CRP Seedings

Correction

The March 21 newsletter contained an error in the winter wheat section with regard to the recommendation for Ally plus 2,4-D. The correct rates are Ally at 0.1 ounce/A plus 1/2 pint of 2,4-D ester.

No-Till Weed Control

Weed control is a key to success with no-till crop production. Control of weeds established at planting time as well as later developing weeds is required. New developments make economical, effective weed control programs available for most situations. One approach is to combine a postemergence and a residual herbicide applied at planting time. Another is to make an early preplant application of residual herbicide and eliminate the postemergence herbicide.

Weed Control in New CRP Seedings

Preplant Treatments

2.4-D ester is an economical choice to control broadleaf weeds at least" one month before seeding grasses or 1equmes. Use 1 pint/acre for most small broad1eaf weeds; increase the rate to 2 pints/acre if large weeds are present at application. Remember that 2,4-D can persist in the soil for up to 4 weeks after application and it may injure grass seedlings and legumes if applied within 30 days of planting.

• Weed Control in winter Wheat
• Weed Control in oats
• New Herbicides and Registrations

Weed Control in Winter Wheat

Even if you're unsure as to how the winter wheat crop will survive the winter, you can definitely count on weeds being present. The most likely candidates are kochia, pennycress, and other mustards. If weeds are present, control measures should be taken soon, but, because of the adverse growing conditions, extra care should be taken this year to make sure the wheat is well tillered before herbicide applications are made.

Weed Control in Oats

Early summer annual weeds such as kochia, smartweed and wild mustard are likely to be problems in oats. Herbicide control options are fewer and risk of crop injury is greater compared to winter wheat. Herbicide applications should be made when the oat crop is in the 3 to 4th leaf stage.

New Herbicides and Registrations

Several new herbicides have been registered recently. There have also been changes in the labels of a number of previously registered herbicides. A brief summary highlighting important points follows.

• Herbicide Carryover Concerns for 1989
• Alfalfa Weed Control
• Miracle Products Via Telephone

Herbicide Carryover Concerns for 1989

The dry conditions experienced during the 1988 growing season have raised concerns about herbicide carryover and recropping practices for this spring. Herbicide residues can be lost through several processes, many of which are dependent on environmental conditions. Dry weather results in less chemical and microbial breakdown as well as reduced plant uptake. Growers need to be aware of potential carryover problems when planning next year's crop rotation.

Alfalfa Weed Control

Warm weather will spur the development of winter annual weeds in alfalfa. Downy brome, pennycress and other mustards can be effectively controlled with herbicide treatments at this time of year. Many times the weed problem isn’t recognized until· the alfalfa "greens up" in the spring--then it t s too late for most herbicides. A word to the wise: "Scout alfalfa fields now and plan control programs accordingly."

Miracle Products via Telephone

“Miracle herbicides" are again being sold by long distance telephone. In one case we know of, the salesperson claims the product can be used in soybeans and corn postemergence to control most annual weed problems and only costs about $69.00 per gallon. The material is actually diquat and contains 1.85% herbicide on a weight basis. There are two problems as we see it: 1) Diquat is not labeled on corn and can only be used in soybeans as a harvest aid and 2) Ortho's formulation of diquat contains 35.3% herbicide and costs about the same.

• Herbicide Carryover Concerns for 1989 No. 88-26 November 8, 1988
• Crop Pest Management Update Conference Scheduled for Kearney in December

Herbicide Carryover Concerns for 1989

The dry conditions experienced during the 1988 growing season have raised concerns about herbicide carryover and recropping practices for next year. Herbicide residues can be lost through several processes, many of which are dependent on environmental conditions. Dry weather results in less chemical and microbial breakdown as well as reduced plant uptake. Growers need to be aware of potential carryover problems when planning next year’s crop rotation.

Crop Pest Management Update Conference Scheduled for Kearney

The second annual Crop Pest Management Update conference for professional agriculturalists is scheduled for December 19 and 20 at the Holiday Inn in Kearney. Registration for the conference begins at 10:00 a.m. on Monday, December 19, followed by an opening noon luncheon and educational sessions starting at 1:00 p. m. General topics range from on-going research· reports to current agricultural issues and a preview of the 1989 insect, disease, and weed control recommendations. Concurrent sessions will include special problems in pest management, storage and quality of grain crops, water management and quality concerns, and a session on "new ideas for old crops." Roger Welsch, well know Nebraska humorist, will be our guest speaker for Tuesday's noon luncheon.

• 1989 Crop Protection Clinic Schedule
• Glean Removed From the Wheat Market
• It is Not Too Late

1989 Crop Protection Clinic Schedule

The dates and locations for the 1989 Crop Protection Clinics have been set. As in the past, we will continue the format of 15-minute presentations with time for questions. Entomologists, Plant Pathologists, and Weed Scientists will be presenting the latest information. More details on the Clinics will be available in our November Newsletter.

Glean Removed from the Wheat Market

DuPont has just announced that the herbicide Glean will no longer be sold for wheat or fallow. The reason for this startling move is growing concern about weed resistance to Glean and perhaps to other herbicides in the sulfonylurea family. Several weed species including kochia, prickly lettuce and Russian thistle have exhibited resistance to Glean after repeated use.

• Control Alfalfa Now - No-Till in '89
• Bindweed Control in Gardens, Windbreaks, and Farmsteads
• Fall Lawn Weed Control

Control Alfalfa Now - No-Till in '89

Eventually alfalfa stands become unproductive and the land must be rotated to another crop. Plowing is an expensive and sometimes not completely effective way of killing alfalfa. Killing the alfalfa with herbicides is more economical than plowing, is very effective, and leaves the soil less subject to erosion. An economical, consistent alfalfa control treatment is a combination of 1 qt. 2,4-D (4 lb./gal) + 0.5 pt. Banvel per acre. The herbicide approach will cost $6.00/A + application cost compared with $10.00-$15.00/A for plowing.

Bindweed Control in Gardens, Windbreaks, and Farmsteads

Field bindweed is a persistent perennial weed. Fall is the best time to control field bindweed, especially in gardens, windbreaks, and around farmsteads. Roundup and 2,4-D are both suited for bindweed control in these situations. There are two big advantages to fall control programs: 1) herbicides are quite effective in the fall, and 2) there is little risk of herbicide damage to desirable vegetation.

Fall Lawn Weed Control

Homeowners are hard to convince that fall is an ideal time to treat lawns for troublesome weeds. The very best control should be expected on dandelions, field bindweed, chickweed, shepherdspurse, henbit, ground ivy, violets, and other broadleaf turf weeds that make fall growth. Excellent herbicides are available. Trimec and Turflon are two products effective on the tough weeds. Apply them anytime in October or early November before a hard freeze. Repeat treatments may be required for ground ivy and violets.

• Rangeland Weed Control with Atrazine
• Musk Thistle Control
• Field Bindweed and Other Perennials
• Leafy Spurge Control

Rangeland Weed Control with Atrazine

Downy brome, hairy chess, pennycress, and mustards can be effectively controlled in rangeland with atrazine. It's not necessary to wait until late fall. Actually the most effective control would be from applications made in early fall. Winter annual weeds start growth in late August and September. Atrazine applications in September would be most effective on the newly germinated weeds. Use 1 to 2 pints of atrazine or AAtrex 4L or equivalent amounts of other atrazine formulations. Bluegrass and intermediate wheatgrass may be injured by the treatments. Aerial or ground applications can be made. According to the label, livestock should not be grazed for 7 months after making fall treatments.

Musk Thistle Control

October and early November are excellent times to control musk thistle providing the weather cooperates. A good fall control program normally eliminates the need for spring control. This is because plants that would flower next summer are normally growing in the fall. However, the success of a fall control program depends on adequate fall rainfall. Dry weather reduces musk thistle seed germination and plant establishment. Where the weather has been dry, there may be no plants to control. Examine the site and determine if the thistle population justifies spraying. Herbicides and per acre rates to use on musk thistle are Tordon 22K at 6 to 8 fluid ounces, 2,4-D + Banvel at 1.0 lb + 0.5 pt, and 2,4-0 at 1.5 to 2.0 lb. These treatments are ranked in order of effectiveness for fall application. Under very dry, cool conditions only Tordon can be expected to perform well. Treatments should be applied after October 1.

Field Bindweed and Other Perennials

Perennial weeds including field bindweed, Canada thistle, and others can be effectively treated with herbicides in the fall. Food storage in the root system of these plants is taking place in the fall. Herbicides applied at this time to plants with excellent top growth readily move down to the roots along with the food. In the fall, temperatures and soil moisture are generally more favorable for plant growth than during the summer, a condition required for best herbicide performance.

Leafy Spurge Control

Special attention should be given to the control of leafy spurge during the fall. Research has shown more consistent control of leafy spurge with fall herbicide treatments compared to spring applications.

• Fall Seeded Crops and Herbicide Residues in the Soil
• Herbicide Use Guide Revision

FALL SEEDED CROPS AND HERBICIDE RESIDUES IN THE SOIL

Herbicide applications made to corn, sorghum, and soybeans must be reckoned with where alfalfa or winter wheat is being considered for fall planting on drought stricken fields.

The guidelines that follow come from labels, product literature, research, and experience. They have been established to protect the user and manufacturer and contain safety factors for average growing conditions. Drier than normal June, July and August weather has undoubtedly prolonged soil longevity of some products.

HERBICIDE USE GUIDE REVISION

Industry reps, extension agents, and all other users of our Herbicide Use Guide--Now is the time to submit your suggestions for our 1989 edition. We appreciate your input of previous years. You have helped make the Nebraska Herbicide Use Guide a most useful weed control aid for farmers, dealers, applicators, farm managers, consultants, extension agents, and others. Your suggestions for the 1989 Guide should reach us by September 16. Send to Weed Science, 362 Plant Science Building, University of Nebraska, Lincoln, NE 68583-0915.

• Late Season Weed Control in Corn and Sorghum
• Bindweed Control Where Wheat is to be Planted
• Double Crop Soybeans
• August Lawn Renovation

Late Season Weed Control in Corn and Sorghum Late season broadleaf weed control in corn and sorghum is possible with 2,4-D. Such a treatment could make harvesting easier and reduce weed seed production. Treatments should be applied no later than flowering stage of weeds for control of seed production. Both corn and sorghum can suffer yield reductions from 2,4-D applied during the flowering period. As a guideline, 2,4-D use on corn can be resumed after the silk turns brown. The use of 2,4-D on sorghum can be resumed after the grain reaches the early dough stage. Sorghum should not be sprayed with 2,4-D between the beginning of head emergence and the milk stage of the grain. These late 2,4-D treatments will not cause lodging or stalk brittleness in the crop.

Bindweed Control Where Wheat is to be Planted

Fall is usually an excellent time to make herbicide applications for field bindweed control. However, healthy new growth on the bindweed is essential for good results. Avoid tillage for at least 30 days prior to treatment. Dry weather in some areas has reduced bindweed growth making it more difficult to control. It would be best to wait for rain and new bindweed growth before treating. This could be too late this fall for land going to wheat. September treatments are usually more effective than August treatments.

Double Crop Weed Control

The early wheat harvest and high soybean prices have prompted some growers to double crop soybeans this season. The biggest concern is controlling volunteer wheat. Both Fusilade 2000 and Poast can be used but slightly higher rates are required compared to annual grasses. Use 1.5 pt./A of Poast with either DASH or COC plus 1/2 gallons of 28% nitrogen per acre. Fusilade 2000 should be used at 1 pt./A with COC or a nonionic surfactant. Broadleaf weed control options are similar to conventional soybean production with the exception that some weeds may be too tall for effective control with postemergence products. In addition, the dry weather may reduce herbicide effectiveness. Check labels to see which surfactants should be included. Avoid long residual herbicides such as Scepter or Classic unless you're prepared to go back to soybeans next spring.

August Lawn Renovation

August is the time to get started with turf renovation. Roundup is a useful herbicide for such projects. Skip one or two mow1ngs so there's good growth on the weeds and grass for herbicide intake and activity. Apply 2 ½ to 3 oz. of Roundup/1000 sq. ft. using 1 gal or less of water. Delay vertical mowing, slicing, coring, and power raking for 7 days.

• Wiper and Bean Bar Applications
• Lawn Care Under Stress Conditions
• Dry Weather and Weed Control

Wiper and Bean Bar Applications

Wiper applicators are popular for controlling tall growing weeds in shorter crops. The weeds should be at least 10" taller than the crop. Roundup is the herbicide of choice for wiper applications in sorghum and soybeans. A conce~tration of 25% Roundup in water is used for control of broadleaf and grass weeds. Shattercane and volunteer corn are ve ry susceptible to Roundup. Roundup concentrations of 20% work well on these plants.

Lawn Care Under Stress Conditions

The heat and drought of the past few weeks has put stress on all plant materials. The best weed prevention in your lawn is to follow cultural practices that keep the lawn thick and healthy. water plays a very important part in growth and cooling of the plant through transpiration. To promote deeper rooting, it is best to water deeply and infrequently. Early morning is the best time to water since the air is relatively calm and evaporative loss is lower. Under extreme drought conditions, it may be necessary to let the turfgrass plant go into a temporary state of dormancy. If you've been irrigating regularly, the plant must go through a gradual hardening-off period with judicial fertilization (use of slow release fertilizers if required), more frequent mowing at a greater mowing height, and a reduction in water applied. Do not stop irrigating the plant all at once, or you may cause extensive plant and root damage. The plant I s system must have time to slow down and convert energy that was used for growth into carbohydrate reserves to use while it is in a dormant state.

Dry Weather and Weed Control

Crops as well as weeds are under stress in dry conditions. Cultivation or the application of an herbicide ·can add to the stress on the crop. With low weed numbers and stressed crops it may be better to tolerate a few weeds or remove them by hand rather than cultivating or spraying.

• Late Season Broadleaf Weed Control in Corn and Sorghum
• Rescue Treatments for Soybeans
• Prepare Now for Conservation Tillage Next Year

Late Season Broadleaf Weed Control in Corn and Sorghum

Corn should not be sprayed with 2,4-D from a week before tassel emergence until after the silks turn brown. Treatments during this critical time often interfere with pollination and cause yield reductions. After the silks turn brown, pollination is complete and 2,4-D use can safely resume. The early planted corn in Nebraska is now in the stage where it should not be sprayed with 2,4-D.

Rescue Treatments for Soybeans

Most broadleaf weeds taller than 6" cannot be consistently controlled in soybeans with postemergence herbicides. There are no soybean herbicides that perform like 2,4-D and Banvel.

Prepare Now for Conservation Tillage Next Year

Control weeds in small grain stubble this summer for planting wheat in the fall or for 1989 spring planting of corn, sorghum, and soybeans. Advances in chemical weed control make possible the control of weeds and volunteer grain without tillage. Weed control without tillage conserves moisture (which is critical this year), reduces wind and water erosion," and cuts back on energy, machinery, and labor costs. Successful chemical weed control requires consideration of certain basics:

1. Straw and chaff behind the combine should be uniformly spread-if not, bale it. Excess straw and chaff interferes with herbicide performance and planting the next crop.

2. A poor job of combining will contribute to poor herbicide performance. Heavy stands of volunteer grain are likely to strain herbicide capabilities.

• Poast in Corn for Shattercane Control
• Pasture and Range Weed Control
• Weed Tour Reminder
• Brush and Woody Plant Control
• Lawn Weed Control

Poast in Corn for Shattercane Control

BASF Corporation has received a Section 18 (emergency exemption) approval for post directional use of Poast herbicide in corn for shattercane control. The label specifies that all applicators must be commercially certified and receive special training by BASF Corporation personnel. Application equipment must direct the herbicide only onto the lower 10 inches of 3D-inch (minimum) corn with the spray nozzles mounted on rigid drop pipes or on skid shoes that follow the terrain. The boom width cannot exceed the planter width. Maximum cane height for control is 12 inches. Experience indicates that Poast will cause excessive corn injury if all label precautions are not followed.

Pasture and Range Weed Control

The growing season is ahead of normal over much of Nebraska and so are pasture and grazing land weeds. Normally the later part of June is the best time to treat broom snakeweed, vervain, goldenrod, sagebrush, snow-on-the mountain, and western ragweed. With the advanced growing season, these weeds should be in the correct stage for treatment over much of Nebraska by mid-June. There's a tendency to treat on the late side rather than too early. A good guideline for treating most perennials is to mow or apply the herbicide when the weeds are in the early flower bud stage. Biennial thistles are an exception and should be treated in the rosette stage.

Weed Tour Reminder

The Nebraska Weed Tour is scheduled for Sidney on June 20 and Scottsbluff and North Platte on June 21. The Tour continues at Clay Center and Lincoln on June 22 and concludes at Concord on June 23.

• Postemergence Weed Control in Soybeans
• Herbicide Drift
• Control Weeds on ACR Acres
• Weed Tour Reminder

Postemergence Weed Control in Soybeans

Timing of postemergence herbicide applications is more dependent on the weed growth stage than crop stage. However, small weeds are more readily controlled than large ones. Basagran, Blazer, Tackle, Scepter, combinations of these, Galaxy, Classic, and Cobra should be used when most susceptible weeds are no taller than 4 inches for best control. Nitrogen solutions (28-0-0 and 32-0-0 at 1 gallon per acre) increase Basagran, Blazer, Classic, and Galaxy activity but weed size "limitations remain. Taller weeds are defoliated but they often recover.

Herbicide Drift

Herbicide injury problems from drift and volatility occur each year. Farm crops as well as gardens, ornamentals and windbreaks are damaged. This not only applies to farm chemicals, but turfgrass herbicides as well.

Control Weeds on ACR Acres

Left unattended ACR acres can turn into a real weed problem next year. Take advantage of the opportunity to clean up a weed problem, don't create a problem for next year.

Weed Tour Reminder

The Nebraska Weed Tour is scheduled for Sidney on June 20 and Scottsbluff and North Platte on June 21. The Tour continues at Clay Center and Lincoln on June 22 and concludes on June 23.

• Herbicide Injury-Replant?
• Yellow Nutseoge Control in Turf
• Delayed Preemergence Herbicides

Herbicide Injury-Replant?

There is some risk of crop 1nJury with the use of any herbicide. Certain herbicides are more likely to injure crops than others. Reasons for herbicide injury include incorrect application rate, nonuniform application (overlapping), herbicide carryover, incorrect choice of herbicide for the situation, unfavorable weather conditions, spray drift, etc.

Yellow Nutsedge Control in Turf

Yellow nutsedge is one of the most troublesome weeds in lawns. Basagran is the safest and most effective herbicide for yellow nutsedge control. Mix 1 oz./gal of water along with an equal amount of surfactant or detergent and apply to vigorous growing plants. If desired control is not obtained with the first application, make additional applications at 10 to 14 day intervals. Because nutsedge can germinate later in the season, additional applications are usually required. As with all postemergence treatments, applications should be made to unmowed turf and mowings made after herbicide treatments should be delayed for 3 to 5 days.

Delayed Preemergence Herbicides

Timely herbicide application is not always possible in the busy planting season. Some but not all preemergence herbicides can be applied early postemergence with good results. However, most of these treatments are more effective when applied preemergence than postemergence especially against annual grasses. A rain or sprinkler irrigation is required after application for best control. The following table lists herbicides that are commonly used in Nebraska and can be used both preemergence and early postemergence.

• Postemergence Shattercane Control in Corn
• Postemergence Heed Control in Onions
• Leafy Spurge Reminder
• Grass Control in Ornamentals

Postemergence Shattercane Control in Corn

Postemergence control of shattercane in corn is limited. Bladex 80W or 90DF used with vegetable oil or a surfactant can be used before corn exceeds the 4-leaf stage. The Bladex label does not claim shattercane control. Our observations are this treatment stunts small shattercane plants but may not kill them. Similar results may be obtained with 2 qt./A atrazine used with crop oil concentrate. Tandem used with Bladex or atrazine will improve activity somewhat. Similarly, Prowl used with Bladex or atrazine before the 5-leaf stage of corn improves activity compared to the triazine alone. While these treatments don't kill the shattercane they set it back allowing the corn to get ahead of the cane. This sets the stage for effective control with cultivation.

Postemergence Weed Control in Onions

Fusilade 2000 is now fully registered for use in dry bulb onions for the control of grassy weeds. Recommended rates are from 12 to 32 oz. per acre and should be applied with a nonionic surfactant or crop oil concentrate. 00 not apply more than 96 oz. per acre per year. 00 not harvest within 45 days after application.

Leafy Spurge Reminder

Leafy spurge is very obvious now in grazing land and along roadsides. The plant is easily seen as the tops of the plants are bright yellow. Small patches should be treated before they spread. The ideal time to treat leafy spurge is from mid-May to early June.

Grass Control in Ornamentals

Perennial grasses such as bromegrass, bluegrass, and quackgrass often become troublesome weeds in iris, peonies, other, herbaceous plantings, and woody ornamentals. Likewise, annual grasses including crabgrass, foxtails, barnyardgrass, and annual bromes present somewhat similar problems. There is an answer.

• Algae and Moss Control in Water and Stock Tanks
• More on Pasture Spraying and Grazing
• Buckbrush and Snowberry--Control Time is Now
• Postemergence Weed Control in Corn

Algae and Moss Control in Water and Stock Tanks

With warmer weather, moss and algae will again make their appearance in plastic nurse tanks used to hold water supplies for spraying operations. Control is simple and inexpensive.

More on Pasture Spraying and Grazing

In the last Newsletter the grazing restrictions following Tordon use were inadvertently omitted. Do not move grazing livestock from Tordon treated pasture to broadleaf crop areas without first allowing 7 days grazing on untreated pastures. Otherwise there are no grazing restrictions with Tordon for meat or dairy animals.

Buckbrush and Snowberry--Control Time Is Now

Buckbrush and western snowberry development is advanced due to ear ly season warm temperatures. Research shows there's a brief two-week period in May during which 2,4-D performs effectively for the control of these two woody plant species. Control time is now -- May 10 to 25 in eastern and southern Nebraska. Northward, initial treatment could be delayed until May 20. Apply 1 1/2 quarts of low volatile 2,4-D ester (4 lbs. active ingredient per gallon) per acre in enough water to provide good coverage.

Postemergence Weed Control in Corn

Dry weather has reduced herbicide performance resulting in poor weed control in some early planted corn. To control escaped grasses, atrazine with oil should be applied when the grass is less than 1 1/2" tall. Bladex 80W or 90DF can also be used but don't apply with oil or if the corn is past the 5-leaf stage. Bladex * atrazine prepacks (Conquest, Extrazine) can also be used to control escaped grasses. Tandem in combination with either Bladex or atrazine increases postemergence activity. If atrazine has already been used as a soil application, be aware of potential carryover problems from an additional postemergence treatment. If Bladex has already been used as a soil application, do not exceed the maximum labeled rate for your soil type. Prowl plus atrazine (Prozine) or Prowl + Bladex can be applied up to the 4-leaf stage of corn.

• 1988 Weed Science Tour
• Summer Hours
• Weather your Herbicide Works or Not
• Pasture Spraying and Grazing Restrictions

1988 Weed Science Tour

The itinerary has been set for the 1988 Weed Tour. This year the tour will progress from west to east across the state. The itinerary is as follows:

Summer Hours

Our summer office hours are from 7:30 a.m. to 4:30 p.m. We are often in the field at this time of year and you may get a more immediate response by contacting the extension agent in your county.

Weather Your Herbicide Works or Not

The dry spring we've had so far may adversely affect some early preplant treatments. All preemergence applications require rainfall to activate them, including early preplant treatments. In some situations, very little or no rainfall has occurred since these treatments were applied. This doesn't present a problem as long as the weeds haven't germinated. However, in some situations there may be enough moisture present to cause weeds to come on.

Pasture Spraying and Grazing Restrictions

Grazing restrictions on sprayed pastures vary with the herbicide and the type of livestock. The only restriction with 2,4-D is that lactating dairy animals not be grazed on treated areas within 7 days after application. There are no restrictions on meat animal grazing.

• New Herbicide Registrations
• Leafy Spurge Control

New Herbicide Registrations

FMC

Command is now registered for use as a preemergence application in the following counties: Adams, Antelope, Boyd, Buffalo, Clay, Cedar, Dawson, Dixon, Franklin, Fillmore, Furnas, Hamilton, Harlan, Holt, Jefferson, Kearney, Knox, Nemaha, Pawnee, Phelps, Pierce, Red Willow, Richardson, Saline, Seward, Thayer, Thurston, Wayne, and York.

Leafy Spurge Control

Leafy spurge, an aggressive plant, continues to spread in Nebraska greatly reducing the carrying capacity of grazing land. The weed is more common across the northern portions of the state but can be found elsewhere. Leafy spurge is a perennial and reproduces from seed as well as from buds on its deep, extensive root system. It reduces forage production and cattle avoid grazing infested areas because it is an irritant and mildly poisonous.

• Musk and Plume less Thistle
• Weed Control in New CRP Seedings

Musk and Plumeless Thistle

Check pastures and rangeland for musk and plumeless thistle. Right now is the perfect time to apply herbicides for their control. Thistles are most susceptible to herbicides when they are in the rosette stage. Because of our warm weather, the rosettes are big, ripe and luscious; the perfect condition for herbicide applications. Musk and plumeless thistle grow under cool conditions. Therefore, herbicides are slower acting but still effective. It's important to apply herbicides before the thistles bolt. It's much better to treat a thistle rosette on a 50° F day than a bolted plant on a 70° F day.

Weed Control in New CRP Seedings

Successful perennial forage establishment depends on the presence of adequate soil water for seed germination and seedling emergence. Weeds can quickly deplete soil moisture and must be controlled to allow grass and legume seedlings to germinate and emerge. In addition, rapidly growing, uncontrolled weeds can form a canopy which shades slower growing desirable plants. Weeds must be controlled on CRP acres to reduce the risks of seeding failure and eliminate possible reseeding costs. Several herbicides have been labeled for use on CRP situations.

• Lawn Weed Control
• No-Till Weed Control
• No-Till Into Alfalfa Sod

Lawn Weed Control

Post-emergence control of dandelions, shepherdspurse, chickweed, and henbit should have been done by now or should be done soon. Granular forms of 2,4-D, Trimec, and similar herbicides are safest to use under most conditions. However, Trimec and other formulations containing dicamba (Banvel) should be used sparingly next to and under trees and shrubs. Turflon from Dow is also labeled for control of many broadleaf weeds. Liquid herbicide formulations should be applied when there is little or no wind movement and with low spray pressure.

No-Till Weed Control

Weed control is a key to success with no-till crop production. Control of weeds established at planting time as well as later developing weeds is required. New developments make economical, effective weed control programs available for most situations. One approach is to combine a post-emergence and a residual herbicide applied at planting time. Another is to make an early preplant application of residual herbicides and eliminate the post-emergence herbicide.

No-Till Into Alfalfa Sod

Killing alfalfa with herbicides is more economical than plowing, is very effective, and leaves the soil less subject to erosion. An excellent seedbed results from herbicide-killed sod whether the crop is planted no-till or following light tillage. The most consistent treatment we have evaluated for alfalfa control is 1 qt. 2,4-D + 0.5 pt. Banvel/A with 2 qt. 2,4-D ester/A a close second. The herbicide approach will cost $5.00-$6.00/A + application compared to $10.00- $15.00 for plowing and seedbed preparation. Alfalfa should be actively growing and have at least 4" of green growth at treatment.

• 1988 Weed Science Tour
• Early Weeds In Winter Wheat
• Combination Herbicides--What's In A Name?

1988 Weed Science Tour

The 1988 Weed Tour has been set for the week of June 20th. This year the Tour will begin in western Nebraska on Monday, June 20th and proceed eastward. A detailed itinerary will be published in April.

Early Weeds in Winter Wheat

We're at it again -- early weed control in winter wheat. The calls are many and the plants are plentiful. Check winter wheat fields now for the presence of pennycress, other mustards, and kochia. If present, control measures should be taken soon.

Combination Herbicides--What's In A Name?

1988 finds many prepackaged herbicide combinations on the market. Evaluating weed control performance, crop safety, and carryover potential of combinations compared with tank mixtures is dependent on the amount of each component in the combination. Sometimes it is difficult to tell how much atrazine is contained in 3 qt. of Bicep or 3 qt. of Extrazine. The following table lists the equivalent amount of each component contained in a gallon or pound of some combination products. The totals don't always add up to 1 gallon or 1 pound of herbicide because the combination products may be more or less concentrated than the individual herbicides.

• Alfalfa Weed Control
• New Soybean Herbicides

Alfalfa Weed Control

Warm weather has prompted the development of winter annual weeds in alfalfa. Downy brome, pennycress and other mustards can be effectively controlled with herbicide treatments at this time of year. Many times the weed problem isn't recognized until the alfalfa "greens up" in the spring -- then it's too late for most herbicides.

New Soybean Herbicides

Several new soybean herbicides have come on the scene in the last few years. A brief summary highlighting important points follows. Single ingredient herbicides are listed first followed by their prepacks.

• 1988 Crop Protection Clinics
• Weed SCience Publications Available

1988 Crop Protection Clinics

The 1988 Crop Protection Clinics are fast approaching. January may seem far away but when you're making preparations, time rolls by in a hurry. The dates and locations for the 1988 Crop Protection Clinics have been set.

Weed Science Publications Available

The Weed Science Society of America is an organization which encourages and promotes the development of knowledge about weeds and their control. The society publishes two journals, Weed Science and Weed Technology. Weed Technology is a new journal which contains research papers which often are of an applied nature as well as feature articles. It should be of interest to scientists as well as agricultural professionals. Membership in the Weed Science Society of America is $40 per year with student affiliate membership $20. Membership includes receipt of Weed Science, Weed Technology, and WSSA Newsletter. Individual subscriptions to Weed Technology can be obtained for $20.

• 1988 Crop Protection Clinic Schedule
• Robert Stougaard Joins Staff at Lincoln
• It's Not Too Late
• What is Your Weed Inventory

1988 Crop Protection Clinic Schedule

The dates and locations for the 1988 Crop Protection Clinics have been set. As in the past we will continue the format of 15 minute presentations with time for questions. Entomologists, Plant Pathologists, and Weed Scientists will be presenting the latest information. More details on the Clinics will be available in our November Newsletter.

Robert Stougaard Joins Staff at Lincoln

Dr. Robert Stougaard has joined the Agronomy Department at Lincoln as an Assistant Professor. His responsibilities will be both Extension and Research with research emphasis on weed control in horticultural crops. Bob is a native of Wisconsin and recently completed his Ph.D. at the University of Nebraska. Welcome aboard, Bob!

It's Not Too Late

A relative hard freeze need not shut down weed control activities. A lot of our tough weeds thrive when temperatures are in the 40' sand 50' s in mid to late fall. Here are some weed control operations that can be done during the next four to six weeks, weather permitting.

What Is Your Weed Inventory?

Take advantage of your time in the combine to assess this years weed control program and inventory your fields for weed infestations. Weeds that have gone to seed will most likely be there next year to cause problems. Write down which weed species are present in each field and draw a map indicating where specific weed problems occur. This will be helpful in determining next years weed control program as well as crop rotation.

• Economize -- Spray Alfalfa Sod Don't Plow
• Bindweed Control in Gardens, Windbreaks, and Farmsteads
• Fall Lawn Weed Control
• Nebraska Crop Pest Management Update Conference

Economize -- Spray Alfalfa Sod Don't Plow

Eventually alfalfa stands become unproductive and the land must be rotated to another crop. Plowing is an expensive and sometimes not completely effective way of killing alfalfa. Killing the alfalfa with herbicides is more economical than plowing, is very effective and leaves the soil less subject to erosion. An economical, consistent alfalfa control treatment is a combination of 1 qt. 2,4-D (4 lb./gal) + 0.5 pt. Banvel per acre. The herbicide approach will cost $5.50/A + application cost compared with $10.00-$15.00/A for plowing.

Bindweed Control in Gardens, Windbreaks, and Farmsteads

Field bindweed is a persistent perennial weed. Fall is the best time to control field bindweed, especially in gardens, windbreak s, and around farmsteads. Roundup and 2, 4-D are both suited for bindweed control in these situations. There are two big advantages to fall control programs: l)herbicides are quite effective in the fall, and 2) there is little risk of herbicide damage to desirable vegetation.

Fall Lawn Weed Control

Homeowners are hard to convince that fall is an ideal time to treat lawns for troublesome weeds. The very best control should be expected on dandelions, field bindweed, chickweed, shepherdspurse, henbit, ground ivy, violets, and other broadleaf turf weeds that make fall growth. Excellent herbicides are available. Apply them anytime in October or early November before a hard freeze.

• Weeds in Winter Wheat
• Rangeland Weed Control with Atrazine
• Musk Thistle Control
• Field Bindweed and Other Perennials

Weeds in Winter Wheat

Wheat seeding is underway. The seeded land may appear clean, however, if set-a-side acres or the 1987 crop had a pennycress or wild brome problem, chances are there will be a similar problem for the 1988 crop. Our worst weeds in winter wheat are those that germinate in the fall with the crop -- blue and tansy mustard, pennycress, wild mustard, cheat, hairy chess, and downy brome.

Rangeland Weed Control with Atrazine

Downy brome, hairy chess, pennycress, and mustards can be effectively controlled in rangeland with atrazine. It's not necessary to wait until late fall. Actually the most effective control would be from applications made in early fall. Winter annual weeds start growth in late August and September. Atrazine applications in September would be most effective on the newly germinated weeds. Use 1 to 2 pints of atrazine or AAtrex 4L or equivalent amounts of other atrazine formulations. Bluegrass and intermediate wheatgrass may be injured by the treatments. Aerial or ground applications can be made. According to the label, livestock should not be grazed for 7 months after making fall treatments.

Musk Thistle Control

October and early November are excellent times to control musk thistle providing the weather cooperates. A good fall control program normally eliminates the need for spring control. This is because plants that would flower next summer are normally growing in the fall. However, the success of a fall control program depends on adequate fall rainfall. Most areas of the state have received moisture sufficient to germinate musk thistle. Dry weather reduces musk thistle seed germination and plant establishment. Where the weather has been dry, there may be no plants to control. Examine the site and determine if the thistle population justifies spraying. Herbicides and per acre rates to use on musk thistle are Tordon 22K at 6 to 8 fluid ounces, 2,4-D + Banvel at 1.0 lb. + 0.5 pt., and 2,4-D at 1.5 to 2.0 lb. These treatments are ranked in order of effectiveness for fall application. Under very dry cool conditions only Tordon can be expected to perform well. Treatments should be applied after October 1.

Field Bindweed and Other Perennials

Perennial weeds including field bindweed, Canada thistle, and leafy spurge can be effectively treated with herbicides in the fall. Food storage in the root system of these plants is taking place in the fall. Herbicides applied at this time to plants with excellent top growth readily move down to the roots along with the food. In the fall, temperatures and soil moisture are generally more favorable for plant growth than during ,the summer, a condition required for best herbicide performance.

• Herbicide Use Guide Revision
• Desiccants for Drying Weeds in Crops
• Volunteer Wheat Control in Fallow
• Your 1987 Weed Control Experiences

Herbicide Use Guide Revision

Industry reps, extension agents, and all other users of our Herbicide Use Guide -- Now is the time to submit your suggestions for our 1988 edition. We appreciate your input of previous years. You have helped make the Nebraska Herbicide Use Guide a most useful weed control aid for farmers, dealers, applicators, farm managers, consultants, extension agents, and others. Your suggestions for the 1988 Guide should reach us by September 18. Send to Weed Science, 362 Plant Science Building, University of Nebraska, Lincoln, NE 68583-0915.

Desiccants for Drying Weeds in Crops

Inquiries have started to come in on desiccants for soybeans, grain sorghum, and corn. The primary concern is the drying of weed growth to facilitate harvest. Timely early harvest is especially important where wheat is to be seeded following harvest.

• Winter Annual Weed Control in Winter Wheat
• Wheat After Atrazine
• Hemp Dogbane Reminder

Winter Annual Weed Control in Winter Wheat

Wheat planting time is fast approaching. Each year many acres of wheat are blindly planted on land where obvious weed problems are likely to develop.

Wheat After Atrazine

We've had inquiries on planting wheat after spring use of atrazine on sorghum and corn. The atrazine label cautions that injury might occur. Moisture conditions strongly influence atrazine persistence. The general opinion is that in eastern Nebraska (l) if 1 1/4 lbs. or less of atrazine were applied in May or earlier, (2) the soil pH is 7 or less and organic matter 2% or greater, and (3) there has been good rainfall or irrigation, there wouldn't be a very high risk to winter wheat planted on such fields.

Hemp Dogbane Reminder

Hemp dogbane is in the correct stage for 2, 4-D or 2, 4-D + Banvel treatment in most areas by late August. Corn in the brown silk and milo in the dough stage can be safely treated. After pod set in adjacent soybean fields is complete, drift effects on soybeans will be minimal. It is important to treat before the dogbane leaves yellow or a frost occurs.

• Late Season Weed Control in Corn and Sorghum
• Bindweed Control Where Wheat is to be Planted
• Reap Dogbane Control in the Pall
• August Lawn Renovation

Late Season Weed Control in Corn and Sorghum

Late season broad leaf weed control in corn and sorghum is possible with 2,4-D. Such a treatment could make harvesting easier and reduce weed seed production. Treatments should be applied no later than flowering stage of weeds for control of seed production. Both corn and sorghum can suffer yield reductions from 2,4-D applied during the flowering period. As a guideline, 2,4-D use on corn can be resumed after the silk turns brown. The use of 2,4-D on sorghum can be resumed after the grain reaches the early dough stage. Sorghum should not be sprayed with 2,4-D between the beginning of head emergence and the milk stage of the grain. These late 2,4-D treatments will not cause lodging or stalk brittleness in the crop.

Bindweed Control Where Wheat Is To Be Planted

Fall is usually an excellent time to make herbicide applications for field bindweed control. However, healthy new growth on the bindweed is essential for good results. Avoid tillage for at least 30 days prior to treatment. Dry weather in some areas has reduced bindweed growth making it more difficult to control. It would be best to wait for rain and new bindweed growth before treating. This could be too late this fall for land going to wheat. September treatments are usually more effective than August treatments.

Hemp Dogbane Control in the Fall

Hemp dogbane approaches the correct stage for treatment with 2,4-D or a combination of 2,4-D + Banvel in late August and early September. Applications should be made after corn is in the brown silk stage or milo is in the soft dough stage. Hemp dogbane roots should have swollen pink buds. Pod set on soybeans in the adjacent area should be complete. The precautions for soybeans are less important where only 2,4-D is used. Treatments can be made until the dogbane leaves begin to yellow. After the dogbane leaves turn color or a frost occurs, treatment will be of little value. Drought stress will reduce control.

August Lawn Renovation

August is the time to get started with turf renovation. Roundup is a useful herbicide for such projects. Skip one or two mowings so there's good growth on the weeds and grass for herbicide intake and activity. Apply 2 1/2 to 3 oz of Roundup/1000 sq ft using 1 gal or less of water. Delay vertical mowing, slicing, coring, and power raking for 7 days.

• Wiper and Bean Bar Applications
• Summer Lawn Weed Control
• Stunted Soybeans

Wiper and Bean Bar Applications

Wiper applicators are popular for controlling tall growing weeds in shorter crops. The weeds should be at least 10” taller than the crop. Roundup is the herbicide of choice for wiper applications in sorghum and soybeans. A concentration of 25% Roundup in water is used for control of broadleaf and grass weeds. Shattercane and volunteer corn are very susceptible to Roundup. Roundup concentrations of 20% work well on these plants.

Summer Lawn Weed Control

Crabgrass, yellow nutsedge, spurge, and yellow woodsorrel are among the most troublesome lawn weeds in July and August. Effective control and safety to other plants is often difficult. In a previous newsletter we gave you information on yellow nutsedge and prostrate spurge control. Here's our suggestions on crabgrass and yellow woodsorrel(oxalis).

Stunted Soybeans

There have been more than the usual reports of stunted soybeans this year. The primary symptom is stunting of plants. Often, but not always, the herbicide in question has been Scepter. The symptoms aren't clear cut and often there has been some disease involvement. Additionally, problems seem to be more serious in eroded areas within a field. These eroded areas are normally less productive regardless of any other problems. High temperature stress in June caused problems on soybeans in general and may be a contributing factor.

• Late Season Broadleaf Weed Control in Corn and Sorghum
• Rescue Treatments for Soybeans
• Prepare Row for Conservation Tillage Rest Year

Late Season Broad leaf Weed Control in Corn and Sorghum

Corn should not be sprayed with 2,4-D from a week before tassel emergence until after the silks turn brown. Treatments during this critical time often interfere with pollination and cause yield reductions. After the silks turn brown, pollination is complete and 2,4-D use can safely resume. Most corn in Nebraska is now in the stage where it should not be sprayed with 2,4-D.

Rescue Treatments for Soybeans

Rescue from Uniroyal is a combination of Alanap and 2,4-DB registered for control of escaped sunflower 12" to flower bud and cocklebur 8" to 24" tall in soybeans. Applications should be made after soybeans are 14" tail or first bloom. Crop oil concentrate or a nonionic surfactant should be used with Rescue. Spray pressures of 40 to 50 psi result in better coverage and weed control. Aerial application and spot spraying are also labeled. Under dry conditions, soybeans may wilt and suffer set back by a Rescue treatment. Recovery may not be complete if the weather stays dry. Weeds under dry conditions may not be completely controlled.

Prepare Now for Conservation Tillage Next Year

Control weeds in small grain stubble this summer for planting wheat in the fall or for 1988 spring planting of corn, sorghum, and soybeans. Advances in chemical weed control make possible the control of weeds and volunteer grain without tillage, Weed control without tillage conserves moisture, reduces wind and. water erosion, and cuts back on energy, machinery, and labor costs.