Tobacco Budworm: Effect of Early-Season Terminal Damage on Cotton Lint Yields and Earliness12

Damage to young cotton, Gossypium hirsutum L., by Heliothis virescens (F.) delayed boll opening and decreased first-harvest yields. Larvae placed on plants in the fourth to sixth true-leaf stage caused more delay and fewer cumulative blooms than larvae placed on plants in the sixth to eighth true-leaf stage. The short-season plant type recovered from early-season terminal damage faster than did the long-season plant type. Lint cotton yields decreased as budworm infestation increased. Total yield reductions (Tamcot SP-37) were significant at 60 and 40% infestation levels in 1978 and 1979, respectively. Because earliness is the primary objective of a short-season production system, terminal damage may negate the advantage of these plant types. Longseason plant types may overcome the effects of terminal loss; however, increased hazards such as late-season tobacco budworm damage and rainfall also must be considered. Damaged plants ultimately produced more vegetation than undamaged plants. This increased plant volume could impede the mechanical operation of the stripper harvester and increase the probability of barky lint and reduced quality.