Population dynamics of spider mite, Tetranychus urticae Koch on okra in relation to abiotic factors of Varanasi region

摘要

Field experiments were carried out to study the population fluctuation of phytophagous mite (Tetranychus urticae Koch) in okra and its relation with different weather variables during 2010 and 2011crop seasons under unprotected conditions Varanasi region. The results revealed that the mite population commenced from 9th and 10th standard week in 2010 and 2011 respectively. The highest population mites per 2.5cm(2) leaf area was recorded on 21st standard week (47.75) in 2010 while the maximum population was recorded in 18th standard week (45.99) during 2011. It was found that the mite infestation was heavy during May in both the years. The maximum number of predatory mites was recorded on 15th standard week (11.86) in 2010 while in 2011 population of predatory mite was highest in 18th standard week (15.98). The population of predatory mites, mean temperature, sunshine hours and wind velocity showed a significant positive correlation with the mite pest where as a negative correlation was established with relative humidity and rainfall.