Reproductive Status of Boll Weevils During Season and Off‐Season of Cotton in the Cerrado of Brazil

ABSTRACT The boll weevil, Anthonomus grandis grandis Boh., presents significant management challenges due to its persistent presence and prolonged cropping season. One hypothesis posits that favorable factors, such as host availability and climatic suitability, contribute to the ongoing reproductive populations throughout the agricultural year. This research assessed the reproductive status of weevils during both the cotton‐growing and off‐seasons, with a focus on adult populations and the reproductive condition of females. Monitoring occurred over two agricultural years in commercial fields. We performed weekly recordings, identifying weevils based on sex and evaluating the reproductive status of females, particularly concerning mating status, sperm viability, and egg development. A total of 94 180 weevils were collected, and the average weekly capture per trap during the cropping season was comparable to that of the off‐season. The percentage of females collected during the growing season was approximately 20% higher than that in the off‐season; however, the percentage of copulated females collected off‐season exceeded that of females collected during the growing season in both years. The spermatozoa in these females demonstrated comparable viability across both periods, with values ranging from 72.6% to 95.9% annually. The presence of different stages of egg development in the reproductive system suggests that females could be engaged in oviposition activities during both the growing and off‐season periods. The findings suggest that a substantial percentage of females continue to be active during the off‐season in the Cerrado from the last generation growing season or emerging in the off‐season from spontaneous cotton plants. The findings indicate that females detect cotton plants for oviposition during this timeframe. Contrary to expectations, the fallow period does not significantly affect the suppression of the weevil population.