Ecology and Management of Tetranychus urticae Koch on okra

This book deals with the seasonal incidence of two spotted spider mite, Tetranychus urticae Koch on okra and its predator, Stethorus punctillum Weise. The management of T. urticae was done with botanicals, Pongamia pinnata L. and Eucalyptus globulus L. Two peaks in T. urticae population was reported first during first fortnight of June (25.69 mites/sq. cm leaf) and second during first fortnight of August,2006(22.50 mites/sq. cm leaf). Predatory beetle also showed two peaks, first during first fortnight of July (0.56 beetle/ leaf)and second during, first fortnight of August,2006(0.48 beetle/ leaf). Strata wise, middle strata harboured significantly more no. of mites and beetles followed by top and bottom strata. A significant positive correlation (r =0.88) was observed between mite and beetle population. Under in vitro conditions, direct spray bioassay showed smaller LC50 and LT50 values as compared to treated food bioassay. Under in vivo, P. pinnata oil (6.24%) was most effective which caused 82.3 percent reduction in T. urticae population follwed by P. pinnata seed extract @9.68% (60.5%)and E. globulus leaf extract @3.92% (36.68%). All extract/oil were found safe to S. punctillum.