Population dynamics and management of red spider mite, Tetranychus urticae, Koch in black gram in new alluvial zone of West Bengal

Spider mite, Tetranychus urticae population first appeared in black gram fields during 15th standard meteorological Week with an initial population load 8.25 mites/2 leaves. In the subsequent time, the population gradually increased and attended its peak population during the 22nd SMW i.e. last week of May with loaded 45.94 mites/ 2 leaves and high temperature showed significant positive correlation with the spider mite population. Regarding spider mite management, Spiromesifen 240 SC @ 1 ml/L recorded highest mortality followed by Diafenthiuron 50 WP @ 1 g/L though the treatments were statistically at par with each other. The highest yield was recorded from Spiromesifen 240 SC treated plots (9.75 q/ha) which was statistically at par with the treatment Diafenthurion 50 WP recorded 9.45 q/ha yield.