تغييرات جمعيت، توزيع عمودي و ميزان پارازيتيسم فصلي شفيره هاي سفيد بالك پنبه Bemisia tabaci (Genn.)(Hom.Aleyrodidae) توسط زنبور پارازيتوئيد Eretmocerus mundus Mercet (Hym. Aphelinidae) روي خيار چنبر در اهواز

Seasonal Population Variability and Vertical Distribution of Sweetpotato Whitefly Bemisia tabaci (Genn.) (Hom., Aleyrodidae) and its Parasitism by Eretmocerus mundus Mercet (Hyrn., Aphelinidae) on Cucumber in Ahwaz

During two years (2000-2001) by using different methods of sampling such as leaf samples, cylindrical and corrugated yellow sticky traps, seasonal population changes of eggs, nymphs, pupae and adults of the whitefly, Bemisia tabaci (Genn.) (Hom., Aleyrodidae) were studied on cucumber in Ahwaz, The rate of seasonal parasitism of pupae by parasitiod wasp Eretmocerus mundus Mercet (Hyn1., Aphelinidae) was also recorded. Results showed that total mean of seasonal parasitism rate on upper, middle and lower leaves were 0, 21.39 and 49.83%, respectively for year 2000. But in 2001, on upper, middle and lower leaves it was 0, 13.15 and 27. 84%, respectively. Population of whitefly increased gradually in mid May and peaked in July and August, then declined at the end of September and early October and it was rare in November. Study on vertical distribution of this pest showed that eggs and adults settled on the upper and middle third of plant but nymphs and pupae were on the middle and lower.