POPULATION FLUCTUATIONS OF AMERICAN BOLLWORM, Helicoverpa armigera (Hüb.) INFLUENCED BY SOME WEATHER FACTORS IN PEA, Pisum sativum (L.) AND COTTON, Gossypium barbadens (L.) FIELDS IN SHARKIA GOVERNORATE, EGYPT

The present study was conducted in Zagazig Distrcit, Sharkia Governorate, Egypt in pea (Pisum sativum) and cotton (Gossypium barbadens) fields under environmental conditions during 2013/2014 and 2014/2015 seasons. Results indicated that the population of the American bollworm male moths, Helicoverpa armigera (Hübner) had five peaks in the two investigated seasons and it started from the 2^nd week of December until the end week of March in the first season and form the end week of Dec. until the 4^th week of April in pea fields in the second one. The highest mean number of moths was recorded during the 4^th and the 2^nd week of March during the aforementioned seasons, respectively. Which being 3.33 and 10.00 moths/trap/week in both seasons, respectively. Statistical analysis showed that the relationship between weekly mean numbers of H. armigera male moths on pea plants, mean temperature and mean RH (%) was positive and negative insignificant in the season of 2014; was negative and insignificant with mean temperature, while RH (%) showed positive and significant in the season of 2015. The tested weather factors of mean temperature and mean RH (%) affected the catch male moths of H. armigera negatively or positively with significant or insignificant differences as explained variance values of 17.18 and 25.46% were recorded during first and second seasons, respectively. In cotton fields, the population of H. armigera male moths was detected in pheromone traps showing 5 and 7 peaks during the period from the 2^nd week of May until the end week of August in the first season, while the populations started form the 4^th of April until 12^th of Sept. in the 2^nd season. The highest number of moths was recorded during the 3^rd of July and 29^th of May in the 1^st and 2^nd seasons, respectively exhibiting 188.00 and 60.00 moths/trap/week in both seasons, respectively. Also, results indicated negative and insignificant correlation between the weekly mean numbers of
H. armigera male moths on cotton plants and mean temperature and mean RH (%) in the season of 2014, but it was positive and significant as well as negative and insignificant correlation in the season of 2015, respectively. The total effect of the tested factors was 15.99 and 24.88% during the seasons of 2014 and 2015, respectively.