Author(s):

Nandini KN and N Srinivasa

Abstract: Biological activity of methanol extracts from leaves of four species of <em>Vitex </em>namely, <em>V. negundo</em> (purple&amp; white types), <em>V. altissima</em>, <em>V. peduncularis</em> and <em>V. trifolia</em>was studied on red spider mite, <em>Tetranychus macfarlanei </em>infesting okra crop. Toxicity effects such as repellency and mortality were determined by releasing adult female mites on okra leaves treated with extracts under laboratory conditions. Among the methanol extracts of different <em>Vitex</em> spp., per cent walk-off of adult mites from treated okra leaf discs differed significantly upto 12 hours. With most of the extracts this repellent property showed only marginal increase from 6 hours to 12 hours. Among the species of <em>Vitex, </em>repellent activity of <em>V. negundo</em> (purple) at 20% concentration and of <em>V. trifolia </em>at 15% concentration was more apparent with 73 per cent walk-off of mites from treated leaf discs. Mortality of adult mites caused by extracts differed significantly between 24 &amp; 72 h interval and also showed significant increase across different test concentrations. <em>V. negundo </em>(purple) extract at 20% recorded the highest mite mortality of 89 per cent followed by 79 per cent mortality caused by <em>V. peduncularis</em> extract treatment at 14% concentration.

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