author(s)
DN Kambrekar, Roopa HS and Shamarao Jahagirdar

abstract
Among the insect pests of soybean, stem fly, Melanagromyza sojae plays an important role in reducing the crop yield. Lack of consistent biological control of the stem fly, Melanagromyza sojae Zehntner has necessitated the studies on impact of the parasitoids on seasonal regulation of stem fly population in soybean. In this investigation the seasonal density dependence of M. sojae parasitoids and the level of parasitism in soybean field was under taken. The results revealed that the population build up of the host insect reached its peak during the mid-season and declined towards the end of the crop season. Two hymenopteran parasitoids each from Eurytomidae and Pteromalidae had a significant impact on M. sojae populations. Average parasitism ranged from 5.00 per cent (Eurytoma sp.) and 3.75 (Chlorocytus sp.) per cent to as high as 35.55 and 32.10 per cent respectively. The mean seasonal trends of M. sojae population and parasitism for the crop season exhibited coexistence of both the parasitoids. The modulation of management practices aimed at conservation of these bio-agents could improve the biological control of M. sojae population under field condition.