Kumar, AnilMonica, Vamguri Latha2017-10-132017-10-132013http://krishikosh.egranth.ac.in/handle/1/5810033067In order to study the bioefficacy of newer acaricides and population dynamics of red spider mite, Tetranychus urticae Koch on brinjal, experiments were conducted in the laboratory as well as in field conditions from the month of March to August 2012. The bioefficacy of newer acaricides against T.urticae was determined in the laboratory at Department of Entomology, S.R.I, R.A.U, where as the field experiment was laid out at the Research Farm of Rajendra Agricultural University, Pusa (Samastipur), Bihar, India. The results pertaining to the present studies have been abstracted below. The absolute population of two spotted mite, T.urticae commenced from the third week of March 2012 and continued its activity till the month of August. Initial population was low and gradually reached peak (6.91 mites per 1 cm2 leaf area) in the first week of June when the weather parameters viz.; maximum and minimum temperature (0C), relative humidity (%) at 07 and 14 hours and recorded 38.3, 27.1, 76 and 47 respectively. There was no rainfall (mm) during this period of observation. These weather parameters were found to be congenial for the population build up of red spider mite. The mite population gradually declined from the month of July and became untraceable in the month of August. The relationship between the population of T. urticae and the weather parameters showed significant positive correlation (r= 0.814) with maximum temperature and significant negative correlation (r= -0.425) with relative humidity at 07 hrs while, non-significant with minimum temperature, relative humidity at 14 hrs and rainfall. All these weather parameters combinedly produced 73.50 percent impact on mite population (R2 = 0.735). Eight newer acaricides including standard check (dicofol) that were tested against T. urticae on brinjal crop in laboratory conditions revealed that the treatments, T8 (dicofol @ 4 ml/ltr), T2 (fenopyroximate @ 0.8 ml/ltr), T3 (spiromesifan@ 0.7 ml/ltr ), T6 (propargite @ 4.0 ml/ltr ) and T1 (diafenthurion @ 0.75 gm/ltr) were highly effective by causing 98% mortality and possessed excellent acaricidal properties. It is quite evident from the data that the per cent mortality increased with increase in exposure period under laboratory condition. Under field conditions also, the bioefficacy of acaricides showed same pattern as that in laboratory conditions. The standard check i.e., dicofol recorded cent per cent mortality in the laboratory and 80 percent mortality in the field conditions respectively.ennullThesis