Role of Trap Crops in Increasing Parasitisation Efficiency of Trichogramma chilonis Ishii in Cotton

The role of trap crops on the parasitisation efficiency of TricllOgramma chilonis was studied at farmer's field at village Khuban (Distt. Ferozepur). Maize, sorghum, pearl millet and marigold were tested as trap crops. One row of trap crop was grown after every 20 rows of cotton crop along with pure crop of cotton. The egg parasitoid was released 13 times during July to September at weekly interval @ 1, 50,000 per hectare. Need based applications of comparatively safe insecticides were also made. The highest mean parasitization (10.48%) was observed when sorghum was used as trap crop and it was significantly higher than all other treatment. The parasitisation when marigold was used as trap crop was also higher (8.08 %) than pure cotton. The mean incidence among green bolls was lowest (2.74 %) when sorghum was used as trap crop and it was significantly lower than other treatments except when marigold (3.52 %) and pearl-millet (3.8 %). The seed cotton yield in pure cotton was lowest (13 q/ha) which was on par with maize (13.1 q/ha) but these were significantly lower than other treatments. The yield was significantly highest (14.8 ql ha) when sorghum was used as trap crop.