ARUNKUMAR HOSAMANIRAMYA, P.R.,2017-06-232017-06-232012-06-30http://krishikosh.egranth.ac.in/handle/1/5810023090Investigations were carried out on biology, seasonal incidence, screening of Bt cotton hybrids and management of yellow mite, Polyphagotarsonemus latus (Banks) with new acaricides at the Department of Agricultural Entomology, College of Agriculture and Main Agricultural Research Station, Raichur, Karnataka during 2011-12 kharif season. Eggs were laid singly on the under surface of leaf, but under crowded conditions they were found on upper surface of leaf. The duration of egg ranged from 2.02 to 2.38 days with a mean duration of 2.07 days and the mean duration of quiescent (resting) stage was 1.42 days. The pre-oviposition, oviposition and post-oviposition periods lasted for 1.31, 7.92 and 1.24 days, respectively. The fecundity was 17.04 to 27.81 eggs with a mean of 5.18 ± 1.12 eggs per day per female. The females lived for a period of 15.66 days while the male longevity lasted for 14.62 days. The length and width of egg, larva, nymph, and quiescent larva was 109.32 ± 4.28 and 72.19 ± 2.14 μm, 154.87 ± 16.41 and 92.68 ± 9.63 μm, 167.45 ± 14.87 and 92.88 ± 13.84 μm and 187.78 ± 10.22 and 114.41 ± 14.60 μm respectively. Irrespective of date of sowing the peak activity of mite was noticed during fourth week of August and first week of September. Correlation studies indicated that maximum temperature showed negative non significant correlation while minimum temperature, rainfall and rainy days showed positive non significant. Screening of 14 cotton hybrids against yellow mite revealed that only MRC 7347 and MRC 7351 were recorded minimum yellow mite population compared to other Bt cotton hybrid. Among the pesticides evaluated fenpyroximate 5 SC @ 25 g.a.i/ha and propargite 50 EC @ 500 g.a.i/ha was found to be superior over other chemicals. Highest net returns of Rs. 76590/ha was recorded in fenpyroximate 5 SC @ 25 g.a.i/ha.ennullThesis