Seasonal Incidence and Effect of Abiotic Factors on Population Dynamics of Sucking Insect Pest Complex of Groundnut

Abstract

Studies on seasonal incidence of sucking insect pests carried out with three dates of sowing viz., early (July 15th), normal (July 30th) and late (August 15th) revealed that the incidence of leafhoppers, aphids and thrips started from 5 to 14 DAS (days after sowing) and continued till harvesting. In early sown crop, the incidence of leafhoppers started from 31 SW and incidence of aphids and thrips started from 30 SW and continued up to 42 and 43 SW for leafhoppers and aphids, respectively and 41 SW for thrips. In normal sown crop, incidence of leafhoppers and aphids started from 32 SW and incidence of thrips started from 31 SW and continued till the end of 45 SW for all the three pests. In late sown crop, the incidence of leafhoppers started from 35 SW and incidence of aphids and thrips started from 34 SW and continued up to 46 and 47 SW for leafhoppers and aphids, respectively and 46 SW for thrips. Correlation studies revealed that incidence of leafhoppers exhibited significant negative correlation with maximum temperature (r = -0.467, -0.442 and -0.464) and rainfall (r = -0.518, -0.529 and -0.742) during all the three dates of sowing (early, normal and late, respectively) and significant negative correlation with minimum temperature in late sown crop (r = -0.448). Aphids exhibited significant negative correlation with maximum temperature (r = -0.469, -0.521 and -0.472) and rainfall (r = -0.443, -0.450 and  -0.721) in all the three dates of sowing (early, normal and late, respectively) while significant negative correlation with minimum temperature in early and late sown crop with r values -0.519 and -0.324.  Thrips exhibited significant positive correlation with maximum temperature (r = 0.522, 0.459 and 0.447), significant negative correlation with rainfall (r = -0.458, -0.465 and -0.451) during three dates of sowing (early, normal and late, respectively) while significant negative correlation with relative humidity in early sown crop (r = -0.616) and significant positive correlation with minimum temperature in early sown crop (r = 0.463).