Abstract
Helicoverpa armigera Hb. is found on many different host plants in Egypt. Field trapping showed that the most preferred hosts were tomato, followed by okra and maize. Highest population density in tomato, okra and maize was recorded in August, during the Successive seasons of 2005 and 2006. Multiple regression analysis showed that only the temperature degree had a considerable and significant influence on the insect populations of H. armigera. Meanwhile, the relative humidity and wind speed did not significantly influence the population. The sex pheromone trap containing (Z)-11-Hexadecenal, (Z)-9-Hexadecenal and (Z)-7-Hexadecenal was highly effective for monitoring the insect pest in tomato, okra and maize fields.