Biology of Jackfruit Shoot and Fruit Borer, Diaphania caesalis (Walker) (Pyralidae: Lepidoptera)

Biology of jackfruit shoot and fruit borer studied under laboratory and fieldcondition indicated, the slight variation in the duration of developmental stages but no variations with respect to morphology of each stages. The eggs were laid singly as well as in small group on tender shoots and fruits. The incubation period, larval and pupal periodvaries from 3.5 to 4.5, 11.1 to 11.7 and 7.6 to 90.0 days during may to June and 4 to 5, 11.7 to 13.1 and 8 to 10 days during September to October, respectively in laboratory and 3.6 to 4.5, 12 to 13 and 9 to 12 days during September to October, respectively under field condition. There were five larval instars with a prepupal period. Pupation was observed in the tunnel in fruits, shoots and in between two leaves. The life cycle varies from 25.6 to 28.7 days and 27.3 to 32.2 days during May to June and September to October, respectively under laboratory and 26 to 30 days and 29 to 36 days during may to June and September to October, respectively under field conditions. The insect could complete 12 generation in a year under laboratory conditions.