Seasonal Abundance of Mite, Tetranychus urticae Koch and Their Correlation with Abiotic Factors on Withania somnifera Linn.

Seasonal abundance inrelation to weather parameters of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) major pest occurred on Withania somnifera L. (Ashwagandha) was studied at B.B.D. Govt. P.G. College, Chimanpura, Jaipur during cropping period from September 2013 to April 2014. The population fluctuations of major pest were recorded at weekly intervals during cropping season. The data revealed that the infestation of T. urticae commenced in the second week of November 2013 (0.09 mites/leaf). The population of mite started to build up gradually and reached to its peak during the third week of December with an average of 6.13 mites per leaf. However, the mite population declined from last week of December 2013 (5.53 mites/leaf) and reaching to its lowest number in the third week of January 2014 (1.07 mites/leaf) and continued to up to second fortnight of March 2014. The results when correlated with all the weather parameters through correlation matrix revealed that maximum temperature (r=-0.5284), minimum temperature (r=-0.6481), morning relative humidity (r=0.4688) and Sunshine hours(r= 0.4949) showed negative correlation but significant relationship with incidence of mites. But, evening relative humidity (r=0.3627) and rainfall (r=-0.3478) had negative correlation and non-significant relationship on mite population during cropping year 2013–2014.