Population Dynamics of Major Insect Pests of Cowpea [Vigna ungiculata (L.) Walp.]

Investigations were carried out on population dynamics of major insect pests that attack cowpea [Vigna ungiculata (L.) Walp.] at Regional Horticultural Research Station, Navsari Agricultural University, Navsari during 2012-13. The results revealed that aphid and jassid population started from 3^rd week of October, reached a peak of 3.4 aphid index and 3.8 jassids/ leaf by 1^st week of December whereas whitefly population started from 3^rd week of October and reached to a peak level of 3.7 whiteflies per leaf in 4^th week of November. Cowpea pod borer population started in 2^nd week of November and reached to a peak level (2.8 larvae/plant) in 1^st week of December and thereafter, decreased gradually. Spotted pod borer population started from 1^st week of November coinciding with the flower initiation and reached to a peak of 2.8 larvae per leaf in 1st week of December. Among various weather parameters, evening relative humidity showed a significantly negative influence on population of almost all pests and minimum temperature showed a significantly negative correlation with aphid, cowpea pod borer and ladybird beetle population.