Degree-day based models for forecasting the flight activity of adult Helicoverpa assulta (Lepidoptera: Noctuidae) in hot pepper fields

Abstract

The flight activity of adult Helicoverpa assulta (Guenee) in hot pepper fields was investigated and degree-day models for predicting adult occurrence were developed based on the patterns observed. There were two patterns (groups of two to three peaks) in the occurrence of H. assulta during the growing season. The spring adult emergence was similar among years, but the summer adult occurrence differed depending on the weather. The two- and three-peak adult flight periods occurred when the cumulative degree-day for H. assulta in early October was 1500 and 1700 degree-days, respectively. Data were then used to develop degree-day based bimodal and trimodal models for prediction of the seasonal two- and three-peak adult occurrences. The applicability of these models for the management of H. assulta is discussed.