Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2006
Publication Date: 10/1/2006
Citation: Suh, C.P., Spurgeon, D.W. 2006. Host-free survival of boll weevils (Coleoptera: Curculionidae) previously fed vegetative-stage regrowth cotton. Journal of Entomological Science. 41:277-284.
Interpretive Summary: Regrowth of cotton following harvest is a concern of boll weevil eradication programs because such plants may extend the opportunity for weevils to reproduce or acquire the necessary fat reserves to overwinter. Most of the concern is directed towards fruiting regrowth cotton because non-fruiting plants cannot support weevil reproduction. However, questions remain regarding the potential contribution of non-fruiting regrowth to weevil host-free survival. We examined host-free survival of boll weevils previously fed non-fruiting regrowth cotton, and found the majority of weevils (>75%) died during the initial three weeks of the host-free period. However, approximately 5% of the weevils survived over 12 weeks without further feeding. The maximum duration of survival was 21 weeks. Given that minimization of boll weevil overwintering survival is commonly regarded a critical goal of eradication programs, our findings suggest non-fruiting regrowth cotton should not be overlooked in eradication zones, particularly in those experiencing unsatisfactory progress or resurgence of weevil populations.
Technical Abstract: The need to minimize populations of overwintering boll weevils (Anthonomus grandis Boheman) in eradication programs is widely recognized, but the potential contribution of non-fruiting regrowth cotton (Gossypium hirsutum L.) to weevil survival has not been directly examined. We conducted experiments in 2002 and 2003 to examine the host-free survival of weevils previously supplied vegetative-stage regrowth cotton. Weevils, one to three days after eclosion, were caged with vegetative regrowth cotton under ambient environmental conditions (2002), or in a controlled environment (23.9 +/- 2°C, 13:11 [L:D] h photoperiod, 2003). Four cohorts of each weevil sex were examined each year. Of the 60 weevils dissected in 2002, 12% possessed the hypertrophied fat bodies associated with diapause and extended host-free survival. In both years, the majority of weevils (>75%) died during the initial three weeks of the host-free period. No differences in host-free survival were detected between weevil sexes, but differences were observed among replicates of the experiment established on different dates. Survival patterns among replicates, however, did not strictly follow a seasonal pattern. Overall, approximately 5% of the weevils survived 12 weeks or longer beyond the feeding period. Maximum observed host-free longevities were 21 and 19 weeks in 2002 and 2003, respectively. Our findings suggest vegetative-stage regrowth cotton should not be disregarded in eradication zones, particularly in those experiencing unsatisfactory progress or resurgence of weevil populations.