Prediction of the cotton leafworm infestation in cotton fields using sex pheromone traps and some weather conditions at Kafr El-Sheikh and Dakahlia Governorates

The present work was carried out at Kafr El-Sheikh and Dakahlia Governorates, aimed to record populations of Spodoptera littoralis (Boisd.) for two years. The changes in population dynamics were studied by liquid pheromone traps during 2003 and 2004 of cotton growing seasons. Results indicated the occurrence of three annual peaks for S. littoralis. Multiple regression between the three tested weather factors (maximum-minimum temperature and relative humidity) and pest catch were calculated and the determination coefficient values were recorded. The combined effect of the prevailing temperature and relative humidity were accounted for 28.4 %, 47.9 % at Biala and 24 %, 38 % at Fowa, Kafr El-Sheikh Governorate of changes in male moths population during 2003 and 2004, meanwhile, Dakahlia Governorate, the effects were 5.9 %, 26.6 % at Aga and 12.8 %, 26.5 % at El Senbellaween during 2003 and 2004 of the changes of the population male moths, respectively. On the other hand, the combined effect of the three prevailing factors was affected for 16 %, 12.9 % at Biala and 6.5 %, 28.6 % at Fowa, Kafr El-Sheikh Governorate on the number deposited of egg- masses during 2003 and 2004, while, it's affected for 37 %, 18.2 % at Aga and 47.6 %, 42.5 % at El-Senbellaween, Dakahlia Governorate during 2003 and 2004 cotton seasons.