VIKRANT, R. SWAMINATHAN AND N. K. BAJPAI

A field trial was laid out to study the population dynamics of major sap sucking insect pests of blackgram when cultivated sole and when niger was intercropped as a barrier crop against blister beetles at the Instructional Farm, Rajasthan College of Agriculture, MPUAT, Udaipur during kharif 2012. The sucking pests began infesting the crop from the first week of August, 2012 and their numerical abundance peaked during September with 16.50 jassids per plant in sole blackgram and 17.25 jassids per plant when blackgram was farmscaped with niger; in a respective manner the numbers of whiteflies per plant were 26.50 and 24.75 on blackgram sole and blackgram with niger; 19.65 and 19.05 thrips per plant in blackgram sole and blackgram with niger and likewise, 43.50 and 37.0 aphids per plant, respectively during the last week of September, 2012. The maximum mean population of blister beetle was 2.75 per plant in the sole crop of blackgram and 2.50 per plant in blackgram with niger. The pod borer (Maruca vitrata) infestation was in traces. The mean density values were the maximum for aphids on blackgram during the crop season cultivated either sole or with niger as barrier crop for blister beetles. Among the abiotic factors of the environment onlyrelative humidity showed a significant positive correlation with the jassid population when blackgram was cultivated sole (+ 0.80) and with niger (+ 0.62).