SESHA MAHALAKSHMI, MSIREESHA, K2016-06-212016-06-212012http://krishikosh.egranth.ac.in/handle/1/67602Studies on “Evaluation of newer insecticides against sucking pests in blackgram” were undertaken during Rabi 2011-2012 at Regional Agricultural Research Station, Lam, Guntur. The incidence of sucking pests i.e both thrips and whiteflies was observed through out the crop growth period in blackgram. Initially, the incidence of thrips was observed from 10 days after sowing while it was from 15 DAS onwards for whiteflies. The peak incidence of thrips was observed during 5th standard week (64 DAS) with a population of 8.26 thrips/trifoliate leaf/plant. All the weather parameters together accounted for 83.23 per cent significant variation in thrips population (R2=0.8323) and maximum and minimum temperatures, morning and evening relative humidities also could independently affect changes in thrips population. The activity of whiteflies was observed from 50th standard week till the end of the crop season. The peak incidence of whitefly population was observed during 5th standard week (64 DAS) with a population of 1.4 nymphs/trifoliate leaf/plant. The multiple linear regression analysis revealed that all the weather factors together were responsible for 53.93 per cent (R2 value) of total variation in whitefly population though it was non-significant. Among the natural enemy complex observed in the blackgram ecosystem, coccinellid beetles and spiders were the dominant predators. The population of natural enemies was observed throughout the crop growth period with a peak abundance during 5th standard week coinciding with peak activity of sucking pests. All the weather parameters together exerted a very high and significant influence of 87.33 per cent on the population of natural enemies. Seed treatment with neonicotinoid insecticides was found to protect the crop from sucking pests upto 25 days after sowing only even at the higher dosage. Irrespective of the insecticides tested, higher doses of the insecticides (10 ml/kg) seed were found effective in controlling the thrips and whiteflies in blackgram. Among all the treatments, imidacloprid 200 SL at 10 ml/kg seed was found to be effective against thrips followed by thiamethoxam 70 WS (10 g/kg seed). While, thiamethoxam 70 WS at 10 g/kg was proved better against whiteflies followed by imidacloprid 200 SL at 10 ml/kg. Phytotoxicity was not observed even at higher doses since there was no reduction in per cent germination and initial plant stand with any of the insecticides. Besides, some phytotonic effect of seed treatment was observed, since there was significant increase in plant height in all the insecticidal treatments compared to control at 30 days after sowing. The disease incidence of YMV recorded at 30 days and 60 days after sowing revealed that lowest YMV incidence was observed in the seed treated plots with higher doses (10 g or ml/kg seed) of thiamethoxam, imidacloprid and thiacloprid. The seed yield of blackgram was high from thiamethoxam treated plot at 10 g/kg seed (1088 kg/ha) followed by imidacloprid at 10 ml/kg seed (1074 kg/ha). Among all the insecticides evaluated as foliar sprays, spinosad 45 SC 0.0135 per cent was found significantly superior in reducing the thrips population followed by fipronil 5 SC 0.005 per cent. Whereas, spiromesifen 240 SC 0.096 per cent was found highly effective against whiteflies followed by buprofezin 10 EC 0.01 per cent, with high per cent reduction in population over control. Among the neonicotiniods tested, imidacloprid 200 SL 0.06 per cent and thiamethoxam 25 WG 0.005 per cent were found promising against thrips, while acetamiprid 20 SP 0.004 per cent and thiacloprid 21.7 SC 0.027 per cent proved better against whiteflies with moderate efficacy. The seed yield of blackgram was highest from spiromesifen 240 SC 0.096 per cent (1188 kg/ha) followed by buprofezin 10 EC 0.01 per cent (1146 kg/ha). However all the treatments were found significantly superior over the untreated control both in terms of pests suppression and seed yield in blackgram.ensowing, insecticides, cotton, seed treatment, diseases, planting, crops, land resources, vegetables, yieldsThesis