Population dynamics of major insect pests of cowpea [Vigna ungiculata (L.) Walp.]

Abstract

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