مقايسه ي پارامترهاي جدول زندگي جمعيت هاي سفيدبا لك پنبه در ايران

Comparative Study on the Life Table Parameters of Local Populations of Cotton Whitefly Bemisia tabaci in Iran

The life table parameters of populations of cotton whitely, Bemisia tabaci (Henn.) (Horn.: Aleyrodidae) as an important pest of cotton fields were studied during 2002. The infested leaves containing nymphs and pupae were collected from Darab, College of Agriculture (Tehran) Qom, Saveh, Gonbad, Gorgan. Varamin, Garmsar, Orsoiich (Kerman) and Shooshtar cotton fields. Experiments were carried out in a growth chamber under 24+2° C, 55±3% RH and 16:8 (L:D) photoperiod on cotton, Gossypium hirsutum L. (Varamin 76 variety). The newly emerged adults from each location were released into a large cage (40x50> 70 cm) set on cotton plants separately. Using mean data obtained on 15 adult whiteflies from each population from 10 local populations, life table parameters were calculated. The most basic life table parameters were age x, surviving from birth to exact ages x (Lx) using this factors for calculation of life table parameters such as number of survivors for successive x and x+l dx , survival period Px, age specific mortality qx, and life expectancy ex and the curves were prepared. The results revealed that proportion of a cohort surviving from birth to exact ages x (Lx) began at 24th day and reached to zero at 48th day, also age specific mortality (qx) began at 22nd day and reached highest at 49th day. Life expectancy (ex) was 26.9 at the initiation of development which reduced to zero at 28th days. Surviving from birth to exact ages x (Lx) were highest at the College of Agriculture (23) and lowest at Gonbad (8) populations. Also life expectancy (ex) was highest (29.72) in College of Agriculture and lowest (24.95) in Varamin population. The results revealed that there were differences between parameters of life table in diverse populations.