Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/11/2002
Publication Date: N/A
Interpretive Summary: It is commonly accepted that female adult boll weevils emerging from their overwintering sites during the spring require access to fruiting cotton plants (i.e., plants with flower buds [squares] or fruit [bolls]) in order to develop reproductively. Consequently, boll weevil eradication and management programs typically do not apply pesticides for overwintered boll weevils until cotton plants begin to produce squares. Observations in a recent field study indicated that a portion of the female overwintered weevil population was capable of producing eggs in the absence of fruiting cotton plants. We examined female reproductive development in weevils fed only non-fruiting cotton plants, and found that female boll weevils could attain a substantial level of reproductive development in the absence of fruiting cotton. This information, in combination with other observations, should prove useful in determining the optimal timing of initial pesticide applications for overwintered boll weevils.
Technical Abstract: Laboratory studies were conducted to examine reproductive development in overwintered female boll weevils fed cotyledon and 4-leaf stage cotton plants for 4, 7, and 10 d, respectively. Compared with baseline dissections, all but one of the feeding regimes (4-leaf stage plants for 4d) significantly increased the percentage of weevils containing oocytes with yolk. All feeding regimes increased the total complement of eggs (developing oocytes and chorionated eggs) present in weevils. The largest complement of eggs occurred in weevils fed cotyledon stage plants for 10 d, followed by those fed cotelydon plants for 7 and 4 d, then by those fed 4-leaf stage plants for 10, 7, and 4 d. None of the feeding regimes, however, significantly increased the percentage of weevils with chorionated eggs, or the mean number of chorionated eggs per weevil. Significant differences among treatments, in terms of chorionated egg production, may have been obscured by the variability between runs and the fact that some weevils may have oviposited prior to dissection. Nonetheless, our study demonstrated that female weevils could acquire a substantial level of reproductive development in the absence of fruiting cotton.