SEASONAL ABUNDANCE OF POTATO APHIDS AND ASSOCIATED NATURAL ENEMIES

Studies were carried out at El-Badrshein. Gin Governorate during two successive years (1995 & 1996). Obtained results showed that in‌festation of potato plants by potato aphids was much higher in summer plantation than in nal plantation in both years of study. On potato sum‌mer plantation, the infestation increased and fluctuated from the begin‌ning of the season till the end of March, then decreased rapidly until crop harvesting in May. In nth plantation, on the other hand, aphid infes‌tation was much lower at the time of plant sprouting, it then increased with the growing season from late October to the end of harvesting time. Statistical analysis of the obtained data showed high partial neg‌ative correlations between aphid population density and each of temper‌ature. wind velocity. photoperiod and rainfall in summer and nih planta‌tions in both years. A positive correlation was found between plant age and aphid population density in the nib plantation, while negative correlation was found in summer plantation. The predaceous and parasitic insects found associated with aph‌ids were Coconella undeampunctata L.; Chrysoperla carnea Steph. ; Syr‌phus corollae F.; Aphid°letes menchonalis Felt.; Onus albchpennis Reuter; Apheimus sp.. Sp:mums sp. and an unidentfied species (Chalcidae).