Date of this Version
Thesis (M.S.)—University of Nebraska—Lincoln, 1955. Department of Entomology.
The substantial increase in soybean production in Nebraska during the past 14 years has caused greater interest in factors affecting its growth and yield. A survey of the insect population on soybeans was made during the summer of 1954 and some tests were made in an attempt to evaluate effects of the control of insects on yield.
Field collections for this study were made in 12 counties of eastern Nebraska. A test plot was also established for the purpose of evaluating the effects of insect control on yield. Thirteen of thirty samples were taken in Lancaster County and four were taken in Buffalo County. The other samples were collected from ten other counties in eastern Nebraska. The counties sampled were selected primarily for their importance in soybean production and secondarily for their accessibility. Most of the collections were made between July 7 and August 2. The small test field was established one-half mile west of Havelock in the Entomology experimental fields.
Studies made by Balduf in Ohio and Kretzschmar in Minnesota indicate that a large number of species regularly invade soybeans. They also found that the families of Cicadellidae, Chrysomelidae, Miridae and Noctuidae contributed the greatest numbers to the totals collected. The results of this study were similar to those of Balduf and Kretzschmar. In addition to the four families mentioned previously, the families Locustidae and Pyraustidae were found to occur in important numbers. These six families constituted 71 percent of the total insects collected in the field and test plots combined.
Yield results from the test plot were not conclusive, possibly because of the small plot size and overlapping effects. Some differences in yield existed between treated plots and the check plots however, and further experimentation may be of value.
Damage from insects on soybeans was noted throughout the summer and it was apparent that such damage could be important if the insects were allowed to build up large populations. The presence of many sucking insects indicates that much hidden damage may occur.
Advisor: Roscoe E. Hill