Ecological Studies on the Peach Green Aphid, Myzus persicae and its Natural Enemies

The population fluctuation, migration and flight activity of aphids vary during the year, because they are affected by various biotic and abiotic factors, among them being the occurrence of variations in temperature and natural enemies' composition. Field studies were carried out in peach-producing-area located in Aga region, El-Dakahlia Governorate during seasons 2019/2020 and 2020/2021. Population of aphids, predators and parasitoids were estimated. Person-product-moment simple correlation coefficients between number of living individuals of Myzus persicae, each of natural enemies or each of temperature or relative humidity were determined. Two peaks of aphid population were annually recorded in April and May-June. Larvae of Aphidoletes aphidimyza, Metasyrphus corolla, and Chrysoperla carnea had two peaks annually, whereas those of Scymnus interruptus had only one. adults of Coccinella undecimpunctata and C. septempunctata recorded two population peaks; and adults of Coccinella novemnotata, Cheilomenes propinqua isis, and C. carnea recorded one peak annually. The population of mummified aphids had two-three peaks annually of abundance in April, June, and July. among the aphidophagous predators, only A. aphidimyza larvae and C. undecimpunctata adults exhibited significantly positive responses to the increase in aphid populations during both seasons of study. In both seasons, parasitism contributed with the highest percentages in the total population mortality of M. persicae, whereas the unknown mortality contributed with the lowest fate. The average of annual mortality was 21.19 and 7.38%, 2.30 and 6.75%, and 1.58 and 1.4% for parasitism, predation, and unknown mortality in the first and second season, respectively.