Oviposition Responses of Soybean Looper (Lepidoptera: Noctuidae) to Varieties and Growth Stages of Soybean

Abstract

Four varieties of soybean belonging to different maturity groups (G) each were planted on 4 dates to measure relative oviposition preference of Pseudoplusia includens (Walker). The varieties were 'Avery' (G IV), 'Hutcheson' (G V), 'Sharkey' (G VI), and 'Braxton' (G VII). Plant growth stages evaluated in 1991 were 2 late vegetative stages (ranging from V8 to V12, depending on variety), and 2 reproductive stages including full bloom (R2) and early pod (R3). In 1992, growth stages included 1 late vegetative stage (ranging from V7 to V12, depending on variety), and R2, R3, and R4 (full pod) stages. In both years, the most mature growth stages for the soybean varieties tested were preferred for oviposition. Moths laid significantly more eggs in the middle to upper plant canopy than in the lower canopy, and the bottom (abaxial) surface of the leaf was preferred over the top (adaxial) leaf surface, stems, blooms, or pods. Knowledge of potential infestation levels of P. includens on soybean varieties at different growth stages assists in selection of planting dates and varieties and enhances sampling efficiency and insecticide control technology.