ECOLOGICAL STUDIES ON SOME PIERCING-SUCKING INSECTS INFESTING COWPEA AT EL-SHARKIA GOVERNORATE, EGYPT

Abstract

the present work was conducted during 2012 and 2013 seasons to survey the Hemipterous insects, aphids, leafhoppers and whiteflies infesting cowpea crop at Abo- Hammad district, El-Sharkia Governorate, Egypt. The seasonal abundance of the aforementioned dominant species and the effects of maximum & minimum temperatures and relative humidity on the pest population was also studied. Plant samples collecting proved to be the most efficient method for collecting aphids and whiteflies, while the sweeping net is more efficient for collecting leafhoppers. A. craccivora, A. gossypii, E. decipiens, E. decedens, C. china and B. tabaci were surveyed. A. craccivora recorded one peak at the 4th week of July in the two study seasons. A. gossypii recorded one peak at the 2nd week of August in 2012 season. In the second season, 2013, two peaks were recorded in the 4th week of July and the 2nd week of August, respectively. E. decipiens recorded two peaks, the first one was recorded at the 3rd and 4th week of July for 2012 and 2013 seasons, respectively, while the second one occurred at the 3rd week of August for the two seasons, respectively. E. decedens recorded two peaks at the 4th week of July and August for the two seasons, respectively. Two peaks for immature B. tabaci were recorded. The first peak was obtained at the end of July for the two seasons of the study. The second one was noticed at the 3rd week of August for the two seasons. Adults of B. tabaci recorded the first peak at the 3rd week of July for 2012 and 2013 seasons. Their second peak occurred in the 2nd week of August for the two seasons. The results clearly indicated the presence of significant and insignificant correlation coefficient and partial regression between numbers of different insect species and maximum & minimum temperature and relative humidity during the two successive seasons.