ECOLOGICL STUDIES ON SOME PREDATORY INSECTS INHABITING COWPEA PLANTS AT MANSOURA DISTRICT.

Abstract

Experiments were carried out at the farm of AgricultureResearchCenter of the Faculty Agriculture, MansouraUniversity during the two successive seasons 2012 and 2013. The obtained results revealed that, six predatory insects inhabiting cowpea plants, these insects namely Coccinella undecimpunctata L., Cydonia vicina nilotica Muls, Cydonia vicina isis Muls, Chrysoperla carnea (Steph.), Metasyrphus corella (F.) and Sphodramantes bioculata (Burm). The result revealed that, C.undicimpunctata had two peaks in the first planting date, three peaks in the second planting date and three peaks in the third planting date during the first season of study. While in the second season of study, this predators recorded four peaks in the first planting date, one peaks in the second planting date and two peaks in the third planting date. Cydonia vicina isis had two peaks occurred in the first planting date, while in the second planting date had three peaks and the third planting date had three peaks. In The second season of study, C. vicina isis had three peaks in the first planting date, four peaks in the second planting date and three peaks occurred in the third planting date. Cydonia vicina nilotica recorded two peaks in the first and second planting date respectively. While, four peaks in the third planting date during 2012. Three peaks; four peaks and three peaks during the first; second and third planting date respectively. Chrysopela carnea had two peaks in the first planting date and three peaks in the second planting date and three peaks in the third planting date during the first season of study. On the other hand, three peaks in the first planting date; four peaks in the second planting date and three peaks in the third planting date. The obtained results cleared that, M.corella had two peaks in the first and second planting dates, respectively during the two seasons of study, while the third planting date had three peaks during the two season of study. Sphadromantis bioculata had two peaks in the first planting date, had three peaks in the second planting date and three peaks in the third planting date during the first season of study. While, in the second season of study had three peaks in the first planting date, three in the second planting date and two peaks in the third planting date. The effect of the temperature and relative humidity on the population density of the predatory insect inhabiting cowpea plants indicated that combined effect of these factors exerted negative or positive significant correlation in the two seasons of study .The results cleared that temperature and relative humidity affected greatly on the population density predatory insect inhabiting cowpea plants.