Abstract
Timing of chemical applications is of key importance in managing pecan weevil, Curculio caryae (Horn). Proper timing is achieved by monitoring pecan weevil emergence and can be improved by predicting delays in emergence due to drought hardened soils. Drought conditions, induced on soil plots, as well as natural soil conditions were used to assess the effects of soil particle size distribution and soil moisture on soil hardness. Soil hardness can be determined by the following: 572.97-9.36(% soil moisture)S.439(% silt)-4.9756(% sand). Simulated rainfall was used to assess variables that affect changes in soil moisture due to rainfall. Changes in soil moisture can be determined by the following: 46.977-0.607(% soil moisture before rainfall)+O.4582(rainfall in cm)-O.6848(% silt). The results of these 2 studies were combined to develop a model for predicting drought delayed emergence of pecan weevil that could be used over a variety of soil types. The model predicts the amount of rainfall needed to reduce soil hardness to the point that weevil emergence is unhindered.
Schraer, Stephen Martin (1996). The effects of soil moisture on pecan weevil emergence and predicting drought delay. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1996 -THESIS -S37.