Seasonal Occurrence of Leaf Miner, Chromatomyia horticola (Goureau) (Diptera: Agromyzidae) and its Parasitoids, Diglyphus spp. on Brown Mustard, Brassica campestris in Kashmir Valley

Chromatomyia horticola (Goureau) was found infesting brown mustard (Brassica campestris) from third week of March till second week of May, during 2006 and 2007, at Srinagar, Kashmir. Per cent plant and leaf infestation by the leaf miners during March-May ranged from 4.16 to 100.0 and 0.46 to 92.73 per cent, with overall mean infestation of 64.13±40.66 and 44.64±39.3, respectively. Average number of miners/leaf ranged from 0.65 to 13.09 (mean = 8.0). Diglyphus spp. were found actively associated with the leaf miner and the extend of parasitism ranged from 4.14 to 97.26% (mean = 38.47±40.7). Correlation between number of leaf miners and per cent leaf damage (r=0.83**, d.f.=7) and between per cent parasitism by Diglyphus spp. and leaf miners (r=0.65*, d.f.=7) were found significant. The correlation analysis exhibited a positive correlation with temperature and negative with relative humidity with respect to infestation.