Factors Influencing Pink Bollworm Pupation and Moth Emergence From Overwintering Larvae in Central Texas

Abstract

Time and rate of moth emergence of the pink bollworm ( Pectinophora gossypiella (Saunders)) from overwintering larvae in two environments over a 6-year period at Waco, Texas are reported. Two major peaks of emergence occurred in 5 of the 6 years from infested open cotton bolls on the soil surface and in 4 years from buried bolls. Usually major peaks occurred 16 to 25 days after an inch or more of rainfall on 1 or more days. Smaller peaks occurred within the same intervals after approximately 0.5 inch of precipitation. Usually major peaks were higher and extended over a longer time as the amount of precipitation on 1 to several days increased. As the temperature increased, the number of days between heavy rainfall and high peaks decreased. Burial of infested open bolls resulted in earlier moth emergence than that from bolls on the soil surface. Also, above-normal spring rainfall resulted in earlier emergence than that occurring in dry springs, from both environments, and consequently a higher percentage of the moths died before suitable fruiting forms Oil cotton were available for propagation. In general, the diapause period was longer than average lind was accompanied by a higher mortality during drought conditions from April through June. As the planting date was delayed, so was the fruiting date, and moth emergence to infest cotton was greatly reduced in both environments.