OVIPOSITION RESPONSES OF SOYBEAN LOOPER (LEPIDOPTERA, NOCTUIDAE) TO VARIETIES AND GROWTH-STAGES OF SOYBEAN

Four varieties of soybean belonging to different maturity groups (G) e ach 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 gr owth stages evaluated in 1991 were 2 late vegetative stages (ranging f rom V8 to V12, depending on variety), and 2 reproductive stages includ ing full bloom (R2) and early pod (R3). In 1992, growth stages include d 1 late vegetative stage (ranging from V7 to V12, depending on variet y), and R2, R3, and R4 (full pod) stages. In both years, the most matu re growth stages for the soybean varieties tested were preferred for o viposition. Moths laid significantly more eggs in the middle to upper plant canopy than in the lower canopy, and the bottom (abaxial) surfac e of the leaf was preferred over the top (adaxial) leaf surface, stems , blooms, or pods. Knowledge of potential infestation levels of P. inc ludens on soybean varieties at different growth stages assists in sele ction of planting dates and varieties and enhances sampling efficiency and insecticide control technology.