Semidwarf Cottons and Bollworm Attack123

Investigations of Heliothis zea (Boddie) attack on cottons differing in growth and fruiting characteristics were conducted in Texas in 1971–72. Numbers of fruits damaged on the indeterminate variety ‘Deltapine 16’, were similar to that recorded on experimental semidwarf determinate strains. Bollworms, as they fed, moved much less on the diminutive cottons in comparison to Deltapine 16. Thresh-hold studies showed that 9000 worms/acre for 3 infestation periods reduced yields 134–144 lb lint/acre. However, the 3 infestation subplots still produced ca. 1000 lb lint/acre. Delayed maturity as a result of the released infestations was recorded in the Deltapine 16 subplots; maturity was unaffected in the experimental semidwarf strain.