روي بادمجان در اهواز ENCARSIA LUTEA و ERETMOCERUS MUNDUS و پارازيتوييدهاي آن BEMISIA TAHRI ديناميسم جمعيت و توزيع عمودي مگس سفيد پنبه

Population dynamics and vertical distribution of cotton whitefly Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) and its parasitoids Eretmocerus mundus and Encarisa lutea on aubergine in Ahwaz

Seasonal poplation dynamics of sweetpotato whitefly Bemisia tabaci (Gennadius) and its parasitoids Eretmocerus mundus (Merect) and Encarsia lutea (Masi) were investigated on aubergine (variety black beauty) during spring and summer 2000 and 2001 in Ahwaz southwest, Iran. Different growht stages of B. tabaci (egg, first to third Iarval inastars, fouth larval instar and adult ) first appeared on plants in the middle of May, increased slowly in June, peaked in the middle of July in 2000 and early July in 2001, and then declined shatply. The population, were very low in September. Fourth larval instars parasitized by E. mundus and E.lutea first appeard on aubergine in the middle of May, ʹthen population increased gradually and in 2000 and 2001 peaked in late August and middy of July respectively. After this period the popultion declined sharply. Average parasitism by E. mmundus and. E. lutea were 24 , %5 in 2000 and 33 , 13% in 2001 respectively. The population of fourth larval instar prasitized by E.mundus were on average 4.5 times (2000) and 6.9 times (2001) higher than 4th larval instars parasitized by. E. lutea. Population fluctuation of these parasitoids indicated that their population dynamics is dependent on the density of host (B. tabaci). Vertical distribution of different growth stages of B. tabaci and also fourth larval instars parasitized by E. mundus and E. lutea were not similar on different parts of aubergine plant. In general the higgest density of eggs, 1st to 3rd larval instars, fourth larval instars and adults of B. tabaci were concentrated on the middle and bottom third of aubergine plants. However, the maximum vertical distribution of 4th larval instars parasitized by E. mundus and E.lutea was on the middle part of the plant.