Population dynamics of two spotted spider mite tetranychus urticae koch on parthenocarpic cucumber in net house (original) (raw)

A field experiment was conducted on parthenocarpic cucumber under net house conditions. during 2016-2017 and 2017-18, to study the population dynamics of spider mite Tetranychus urticae Koch. The eggs and other active stages were observed, which revealed that egg (21.2 and 25.5 eggs/ ten leaves) and active stages (15.2 and 18.8 active stage/ ten leaves) were at peak during 22 nd and 21 st standard meteorological week, respectively during 2017 and 2018. Correlation coefficients with weather parameters showed a significant and positive relationship between temperature-with r values for temp Max , temp Min and Temp Avg with 'r' values being 0.55, 0.60 and 0.59, respectively (significant at p= 0.01). Relative humidity (RH M and RH Avg) showed significant negative correlation (r =-0.59 and-0.51; significant at p= 0.01). The stepwise regression analysis revealed that Temp Min was the weather factor responsible in determining abundance of T. urticae and its buildup to the extent of 44%.