Consumption and Development of Velvetbean Caterpillar 1 as Influenced by Soybean Phenology 2

Effects of soybean, Glycine max (L.) cv. Bragg, phenology on leaf consumption and development of the velvetbean caterpillar (VBC), Anticarsia gemmatalis Hubner, were investigated at 26.7 ± 1° C, 14L:10D photoperiod, and RH > 80%. Soybean plant stages were designated as early vegetative (V2–V5), late vegetative (V5–V8), flowering (R1–R2), pod set to pod fill (R4–R6), and senescent (R7–R8). Mean leaf fresh weight consumed by 4th- and 5th-instar VBC larvae declined as plant phenology progressed. Dry-weight consumption did not tend to decline with plant phenology and was more uniform for all plant growth stages than the freshweight values. Mean larval development time varied from 12.6 to 14.3 days, and mean time from egg hatch to adult varied from 21.9 to 23.4 days when larvae were fed late-vegatative and senescent foliage, respectively. Larvae fed senescent leaves produced pupae with reduced weight. Sex ratio (male/female) varied from 0.83 (flowering stage) to 1.37 (late-vegetative stage).