Occurrence of stem fly, ophiomyia phaseoli in major pest status in black gram in souther zone of Andhra Pradesh, India

The infestation of Stem fly, (Tryon) Ophiomyia phaseoli is being observed regularly in Black gram during rabi in Southern zone of Andhra pradesh, India. Two black gram varieties ,i.e, TBG104 and PU31 were tested with four dates of sowing during rabi 2018 -19 to record the incidence of stem fly, Ophiomyia phasioli. Four sowings includes first fortnight of November to Second fortnight of December. Data on the infestation levels of stem fly was recorded at 15 days interval during the crop period (upto 85 DAS). As initial symptoms, the wilting and drying of first and second tender leaves was noticed. Later, after thickening of the stem, in majority of the infested plants, the damage was observed at basal portion of the stem just above to the ground level. The stems appeared thickened and in that portion, consisted longitudinal spits. The tunneling was observed downwards. With the puparia seen in affected stems, the stem fly infestation was confirmed. The infestation of stem fly was very high during February and March i.e in December sown plots. In D1, D2, D3and D4 plots, the average per cent stem fly incidence recorded was 12.88, 21.47, 25.42 and 48.00 respectively. No much variations were observed between the 2 varieties with respect to stem fly infestation. In TBG104 and PU31, average infestation levels of 25.46 and 28.43 % were recorded. . From the weather data and the data on stem fly infestation levels, it is clear that, most influencing factor is Maximum temperature. Maximum temperature from 36 to 380C is very congenial for stem fly that was existed during II FN Feb – II FN March. During this period, the per cent infestation was high even maximum 100% also. The relative humidity Morning and Evening recorded during the period of high incidence were 68 to 76% and 22 to 32%.