DINESH YADAV* R. SWAMINATHAN AND O.P. AMETA

The diversity of flea beetles and their population dynamics on mustard and radish was investigated during rabi 2009- 10 at the Department of Entomology, Rajasthan College of Agriculture, MPUAT, Udiapur. The flea beetles collected from mustard and radish belonged to the two genera, Phyllotreta and Chaetocnema; of which, Phyllotreta dominated forming 86.48 and 82.77 per cent of the total on mustard and radish, respectively. The species, Phyllotreta chotanica Duvivier and Chaetocnema basalis Baly were the most frequent on these crops. The genus Chaetocnema was most speciose with four species, while Phyllotreta was represented by two species. Quantitative analysis showed that Ph. chotanica population peaked during the third and fourth weeks in February 2010 with a mean of 39.8 and 54.4 beetles per plant on mustard and radish, respectively. The mean atmospheric temperature and relative humidity had mild negative correlation (r = -0.012 & -0.404) with the beetle population on mustard, but a mild positive correlation (r = +0.293) with sunshine; whereas, the flea beetle population on radish showed a significant positive correlation with mean atmospheric temperature (r = +0.89), but a significant negative correlation with mean relative humidity (r = - 0.83).