Influence of Different Cotton Fruit Sizes on Boll Weevil (Coleoptera: Curculionidae) Oviposition and Survival to AdulthoodS.

Understanding the critical host plant factors that determine oviposition behavior and survival of boll weevil, Anthonomus grandis grandis Boheman, on cotton, Gossypium hirsutum L., is important for developing successful pest management strategies. However, published information is both conflicting and limited regarding how different cotton fruit sizes affect boll weevil oviposition choices and subsequent larval survival to adulthood. Consequently, we used a standard based on fruit size diameter to evaluate boll weevil feeding and oviposition punctures, and survival to adulthood on 10 different cotton fruit sizes: squares of diameter 1.5-2.0 (pinhead), 3.0-3.5 (matchhead), 5-6, 7-8, or 9-10 mm; candle; and bolls of diameter 10-15, 15-20, 20-30, or \u3e30 mm. Oviposition and feeding punctures were significantly affected by cotton fruit size. Females did not oviposit in pinhead squares. The fewest eggs were oviposited in boll sizes \u3e30 mm. The highest number of eggs was recorded in square sizes of 5-6 and 7-8 mm. Boll weevil survival to adulthood was highest on square sizes of 7-8 or 9-10 mm (58.6-59.7%). No survival occurred in matchhead squares or bolls \u3e30 mm. Duration of development was longest on boll sizes of 15-20 and 20-30 mm (18.2-18.8 d). The growth index (percentage immature survival divided by immature developmental time) of female boll weevils was 2.8-fold higher in 7-8- or 9-10-mm diameter squares than in 20-30-mm diameter bolls. This study will improve our capacity to develop methods to predict fruit losses and changes in boll weevil populations in the field, given a starting density of fruit suitable for oviposition, and a corresponding initial population density of weevils

Influence of Different Cotton Fruit Sizes on Boll Weevil (Coleoptera: Curculionidae) Oviposition and Survival to AdulthoodS.

Understanding the critical host plant factors that determine oviposition behavior and survival of boll weevil, Anthonomus grandis grandis Boheman, on cotton, Gossypium hirsutum L., is important for developing successful pest management strategies. However, published information is both conflicting and limited regarding how different cotton fruit sizes affect boll weevil oviposition choices and subsequent larval survival to adulthood. Consequently, we used a standard based on fruit size diameter to evaluate boll weevil feeding and oviposition punctures, and survival to adulthood on 10 different cotton fruit sizes: squares of diameter 1.5-2.0 (pinhead), 3.0-3.5 (matchhead), 5-6, 7-8, or 9-10 mm; candle; and bolls of diameter 10-15, 15-20, 20-30, or \u3e30 mm. Oviposition and feeding punctures were significantly affected by cotton fruit size. Females did not oviposit in pinhead squares. The fewest eggs were oviposited in boll sizes \u3e30 mm. The highest number of eggs was recorded in square sizes of 5-6 and 7-8 mm. Boll weevil survival to adulthood was highest on square sizes of 7-8 or 9-10 mm (58.6-59.7%). No survival occurred in matchhead squares or bolls \u3e30 mm. Duration of development was longest on boll sizes of 15-20 and 20-30 mm (18.2-18.8 d). The growth index (percentage immature survival divided by immature developmental time) of female boll weevils was 2.8-fold higher in 7-8- or 9-10-mm diameter squares than in 20-30-mm diameter bolls. This study will improve our capacity to develop methods to predict fruit losses and changes in boll weevil populations in the field, given a starting density of fruit suitable for oviposition, and a corresponding initial population density of weevils

Effects of Burial and Soil Condition on Postharvest Mortality of Boll Weevils (Coleoptera: Curculionidae) in Fallen Cotton Fruit

Effects of soil condition and burial on boll weevil, Anthonomus grandis grandis Boheman, mortality in fallen cotton, Gossypium hirsutum L., fruit were assessed in this study. During hot weather immediately after summer harvest operations in the Lower Rio Grande Valley of Texas, burial of infested fruit in conventionally tilled field plots permitted significantly greater survival of weevils than in no-tillage plots. Burial of infested squares protected developing weevils from heat and desiccation that cause high mortality on the soil surface during and after harvest in midsummer and late summer. A laboratory assay showed that burial of infested squares resulted in significantly greater weevil mortality in wet than in dry sandy or clay soils. Significantly fewer weevils rose to the soil surface after burial of infested bolls during winter compared with bolls set on the soil surface, a likely result of wetting by winter rainfall. A combination of leaving infested fruit exposed to heat before the onset of cooler winter temperatures and burial by tillage when temperatures begin to cool might be an important tactic for reducing populations of boll weevils that overwinter in cotton fields