B.S.NandihalliA.Sitharama.Sarma2016-07-232016-07-232010http://krishikosh.egranth.ac.in/handle/1/69520Investigations on seasonal incidence, screening of brinjal varieties for their reaction against brinjal mite, Tetranychus spp., effect of temperature and relative humidity on the biology of T. macfarlanei, relative toxicity of acaricides under laboratory conditions and screening of acaricides under field conditions against Tetranychus spp. and resurgence studies on brinjal mite, Tetranychus spp. were carried out during 2005-07. Studies on seasonal incidence of brinjal mite, Tetranychus spp. revealed that their incidence was more during summer followed by rabi and kharif seasons and the natural enemies also followed the same trend reaching their peak with peak infestation of the mites. Studies on biology of T. macfarlanei at different temperatures and relative humidities revealed that the duration of different stages, fecundity and adult longevity decreased with increase in temperature and decrease in relative humidity. Life table studies of T. macfarlanei revealed that the net reproductive rate (Ro), the mean generation time (Tc) and the innate capacity for increase in numbers (rm) increased with increase in temperature. Among the twelve varieties screened for their reaction against Tetranychus spp., Arka Nidhi recorded lowest mite population during both the years and also recorded on par yield with the best yielded variety Kalyan. The varieties, Arka Nidhi and Arka Keshav were moderately resistant. From the relative toxicity studies, it can be summarized that dicofol was the most effective acaricide (LC50=206.177 ppm) followed by spiromesifen (LC501061.64 ppm), propargite (LC50=2061.64 ppm), milbemectin (LC50 =2652.87 ppm) and diafenthiuron (LC50=3306.34 ppm). The field screening of acaricides revealed that spiromesifen 240 SC has recorded the lowest mite population of 5.90 mites/6.25 cm2 leaf area followed by diafenthiuron and dicofol and the net returns were highest in spiromesifen (Rs. 1,04,500/-) followed by dicofol (Rs. 82,800/-). The resurgence percentages indicated that bifenthrin caused more resurgence (16.65%) followed by cypermethrin (15.53%) and fenvalerate (13.36%).Thesis