Exploration of a biological control agent and evaluation of conventional control measures to manage cucumber moth, an emerging pest of cucurbitaceous vegetables in Bangladesh

Abstract

Cucumber moth, Diaphania indica (Crambidae: Lepidoptera) is a serious pest of cucurbitaceous vegetables in many countries. This pest has also been reported in Bangladesh. However, no proper effort has been made to manage it successfully. Inappropriate control measures may increase the management costs as well as detrimental to the environment and non-target organisms. Larvae of D. indica, larvae were collected from the field and reared in the lab to find out natural control agents. About 41% larvae were found parasitized by a natural parasitoid, Apanteles taragamae. On an average, 16 parasitoid adults were developed from a single parasitized larva. Efficacy of commonly used control measures (such as neem oil, mahogany oil, handpicking, deltamethrin insecticide and cypermethrin insecticides) were evaluated against D. indica in the field on snake gourd and ridge gourd. All control measures produced significant differences to reduce per cent leaf infestations and the number of larvae per plants comparing to the untreated control plants. Among the treatments, neem oil and deltamethrin were found highly effective. Mahogany oil and cypermethrin were found as moderately effective and handpicking was found as least effective among the treatments. Neem oil-cum-deltamethrin approach can be recommended to control D. indica. Use of A. taragamae will give sustainable management of D. indica if commercial release is available.