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Thesis (M.S.)—University of Nebraska—Lincoln, 1976. Department of Entomology.


Copyright 1976, Bruce J. Monke. Used by permission.


All fields involved in this study were located in Clay County, Nebraska and were farmed by cooperators in the Pest Management Project. Many of the field procedures were adapted from those used by the University of Nebraska Agronomy Department Outstate Testing Service. The purpose of this study was to examine, under Nebraska conditions, the accuracy of the currently accepted guidelines for determining the necessity of greenbug control on grain sorghum.

The data in this study do not support specific guidelines based only on greenbug populations or plant damage sustained due to greenbug feeding, for controlling greenbugs on susceptible grain sorghum. The data do suggest, based upon additional factors, that an optimum time to control greenbugs probably exists. The timing, however, may depend upon growth stage of the plant and length of time in that stage, previous levels and duration of the greenbug infestation, available moisture, amount of damage already sustained by the sorghum, and the number of greenbugs present.

There appears to be a high degree of inherent variability in the experimental material. This variation (greenbug populations, grain production, varietal differences, fertility, and moisture) would require that sufficient replication be used in any further evaluations to ensure enough precision to derive meaningful conclusions.

Advisor: David L. Keith.

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