Effect of weather factors on the incidence of major insect pest on okra

Abstract

An investigation on the seasonal incidence of sucking pests and fruit borers ants its natural enemies on okra was carried out at the Department of Agricultural Entomology, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani during Kharif 2018. The results revealed that the population of sucking pests viz., aphid (Aphis gossypi), jassid (Amarasca biguttula biguttula) and whitefly (Bemisia tabaci) ranged between 9.20 - 56.40, 3.60 - 22.0, 1.40 -14.80 per three leaves, respectively. The first appearance of sucking pests was noticed in 29th SMW, whereas its peak period was 36th, 37th and 38th SMW, of aphid, jassid and whitefly, respectively. The first appearance of fruit borers i.e. Earias vittella and Helicoverpa armigera was noticed in 30th and 33rd SMW with 0.9 and 1.8 larvae/plant, respectively, thereafter it was increased gradually and reached its peak of 6.4 and 3.6 larvae/plant in 39th and 37th SMW, respectively. As regards correlation studies with weather factors, aphids and E. vittella shows negatively significant correlated with rainfall. Whitefly and E. vittella shows negatively significant correlated with maximum temperature. Aphids, jassids and ladybird beetles showed positively significant correlation with evening relative humidity. E. vittella had negatively significant correlation with wind velocity and positively significant correlation bright sunshine hours.