Longevity of Overwintered Boll Weevils (Coleoptera: Curculionidae) On Pre-fruiting Cotton

Field-cage studies have indicated that prefruiting cotton (Gossypium hirsutum L.) is not nutritionally adequate to support extended longevity of overwintered boll weevils (Anthonomus grandis Boheman), but these studies did not separate the respective effects of environment and nutrition on survival. The longevity of trapcaptured overwintered weevils fed pre-fruiting cotton under controlled conditions was examined. Weevils held at 24 ± 1°C under a 12:12 [L:D] h photoperiod were supplied water, water plus cotyledon stage plants, or water plus four-leaf stage plants. The longevity of both sexes was similar, and averaged 81.7, 61.8, and 6.8 d for cotyledon stage plants, four-leaf stage plants, and water alone, respectively. Temporal patterns of mortality also differed among the feeding treatments. Longevities were substantially greater than those previously reported, indicating prefruiting cotton has greater nutritional value than is generally recognized. These results indicate that factors other than the nutritional status of cotton seedlings likely play important roles in the effectiveness of cultural practices, such as uniform delayed planting. Continued study of the ecology of overwintered weevils should provide additional insights that will permit more effective implementation of early-season cultural practices.