Studies on the Biology of Fruit and Shoot Borer (Earias vittella) on Okra Crops

Abstract

Okra (Abelmoschus esculentus (L.) Moench) is an important vegetable crop, and the fruit and shoot borer, Earias vittella, is a major pest affecting its vegetative and reproductive stages. The present laboratory study was conducted to examine the biology, developmental duration, morphometric characters, adult longevity, sex ratio and fecundity of E. vittella on okra. Infested fruits were collected from the field and maintained under laboratory conditions to establish the initial culture. The insect completed its life cycle through four stages: egg, larva, pupa and adult. The incubation period ranged from 3 to 5 days, with a mean duration of 3.6 ± 0.80 days. The larval stage consisted of five instars and was the longest developmental phase, with a total larval duration of 13 to 19 days and a mean of 15.75 ± 1.58 days. The prepupal and pupal periods averaged 1.35 ± 0.47 and 7.8 ± 0.83 days, respectively. Adult males lived for 6 to 13 days, while females lived for 7 to 15 days. Female fecundity ranged from 95 to 309 eggs, with an average of 210.33 ± 63.50 eggs. The sex ratio was recorded as 1:0.66. The findings provide baseline information on the developmental biology of E. vittella under laboratory conditions.