Karnatak, A.K.Shivashankara2018-12-262018-12-262018-01http://krishikosh.egranth.ac.in/handle/1/5810086313The study on “Studies on efficacy of pre-mix insecticide combination on major insect pests and natural enemies in sugarcane ecosystem” was carried out during 2014-16 at N.E.B.C.R.C. of G.B.P.U.A & T. Pantnagar, Uttarakhand, India. A total of seventeen predominant insect-fauna were recorded, out of which eleven are insect pests and along with spiders. Among the insect fauna, six insect species belonged to the order lepidoptera that comprised of borer complex of sugarcane and Epiricania melanoleuca, five to hemiptera (sucking pests), one to coleoptera (lady bird beetle), one to Isoptera, and one each to orthoptera, dermaptera, neuroptera, hymenoptera and spider species belonged to araneae (Arachnida). The incidence of shoot borer was recorded from 14th to 26th SMW and reached its maximum in month of May and found highly negative significant with RHmax; black bug from 16th to 27th SMW attaining its maximum in the 21st standard week and found positive highly significant correlation with Tmax; Pyrilla perpusilla from 32nd to 44th SMW attaining its maximum in the 40th (I season) and 37th (II season) SMW and found negative significant correlation with rainfall respectively. The results of insecticides efficacy shows that the soil application of Pre-mix insecticide imidacloprid+acephate @3000 g/ha was most effective followed by its next doses @2500 g/ha and @2000 g/ha in reduction of termite, white grub, early shoot borer infestation, Pyrilla and black bug population during both the seasons. The relatively least harmful treatments for Coccinella spp. and predatory spiders were the soil application of Imidacloprid+acephate @2000, 2500 and 3000 g/ha respectively, and among checks the imidacloprid soil application respectively. Meanwhile the Imidacloprid+acephate chemical did not cause phytotoxicity on sugarcane up to 10 days in any form of spray even @ 2500 and 5000 g ha per ha. Further, the efficacy of treatments on yield shows that the plots received Imidacloprid+acephate soil application @3000 g/ha was recorded with maximum cane yield of 121.33 and 104.40 tonnes per ha followed by the soil application of Imidacloprid+acephate @2500 g/ha with 110.80 and 94.55, and @2000 g/ha with 99.07 and 85.10 tonnes per ha, whereas the soil application of phorate recorded highest yield of 84.93 and 75.28 tonnes per ha among the checks during 2014-15 and 2015-16 respectively. Likewise, the correlation between reduction of insect damage/infestation vs. yield shows that, there is highly positive significance between white grub, termites, early shoot borer, black bug and pyrilla population against cane yield.ennullThesis