Dicamba tank mixtures and formulations and their effects on sensitive crops during cleanout procedures

Authors

Vinicius Velho, University of Nebraska-LincolnFollow

First Advisor

Chris A. Proctor

Second Advisor

Greg R. Kruger

Third Advisor

Joe D. Luck

Date of this Version

Summer 7-17-2022

Document Type

Thesis

Citation

Velho, V (2022) Dicamba tank mixtures and formulations and their effects on sensitive crops during cleanout procedures. Master's thesis. Lincoln, NE: University of Nebraska

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Agronomy, Under the Supervision of Professor Christopher A. Proctor. Lincoln, Nebraska: May 2022

Copyright © 2022 Vinicius Velho

Abstract

The introduction of dicamba-tolerant (DT) soybeans (Glycine max L. Merr) and cotton (Gossypium hirsutum L) in 2017 provided an additional tool for herbicide resistant weeds management. In the subsequent years, off-target movement of dicamba allegedly caused damage to sensitive crops and vegetation.

Possible causes of off-target movement include tank contamination, physical drift, and volatility. Additional products, such as herbicides to control grass, are often added to tank with dicamba, which is used to control broadleaf weeds, to increase the spectrum of control and application efficiency. Dicamba products registered for DT crops require the use of drift reducing agents to mitigate unintended effects to adjacent crops.

Sprayers are complex machines with valves, hoses, tanks, and nozzles that can retain herbicide residues and cause symptomology and/or injury to crops if proper cleanout procedures are not performed. Recommended cleanout procedures can be found in dicamba product labels, but there is no information available reporting the effect of tank mixtures or different dicamba formulations on retention of residues.

The objective of this research was to: 1) evaluate the dicamba retention of potential tank mixtures with dicamba and drift reducing adjuvants, clethodim as well as tank-cleaning agents on non-DT soybeans, 2) evaluate the cleanout procedures of commonly used dicamba products, on non-DT soybean, and 3) investigate how the rinsate following cleanout procedures of dicamba mixtures affect such as soybean, cotton, tomatoes (Lycopersicon esculentum) and peanuts (Arachis hypogaea L.).

Advisor: Christopher Proctor