Abstract
Okra (<em>Abelmoschus esculentus</em> (L.) Moench) is ravaged by many insect pests from germination to harvest. Sucking pests in the early stage and the fruit borers, <em>Earias vittella</em> Fabricius and <em>Helicoverpa armigera</em> (Hübner) in the later stage causes extensive damage to fruits causing 69 per cent yield loss. In recent years, increased interest has been shown towards biological control following unsatisfactory results with the application of conventional insecticides. Horticultural crops, chiefly fruit crops, provide a stable environment offering good opportunity for biological control. Hence, investigations were carried out during 2007-2008 to assess the potential of braconid parasitoids against okra fruit borers. The results revealed that the combination of <em>Trichogramma chilonis</em> + <em>Chelonus blackburni</em> + <em>Bracon brevicornis</em> and <em>C. blackburni</em> + <em>B. brevicornis</em> were more effective to lower larval population of <em>E. vittella</em> and <em>H. armigera</em> which was next to Endosulfan 35 EC after three releases/spray. Similar trend was also observed for per cent fruit damage on both number and weight basis. Combination of <em>T. chilonis</em> + <em>C. blackburni</em> + <em>B. brevicornis</em> and <em>C. blackburni</em> + <em>B. brevicornis</em> recorded higher yield which was on par with endosulfan 35 EC. The results of the trials widened the scope of utilizing the braconid parasitoids in the biosuppression of fruit borers on okra. <br /> DOI: <a href="http://dx.doi.org/10.4038/tar.v21i1.2585">http://dx.doi.org/10.4038/tar.v21i1.2585</a> <em>Tropical Agricultural Research</em> Vol. 21(1): 39-50 (2009)
Highlights
Okra (Abelmoschus esculentus (L.) Moench) which belongs to Family Malvaceae is one of the important vegetable crops grown throughout the tropical and warm temperate regions of the world
Earias vittella Fabricius and Earias insulana Boisdual in the later stages of crop growth causes extensive damage to fruits resulting in 69% yield loss (Atwal and Singh, 1990)
The larval parasitoid, Bracon brevicornis Wesmael (Braconidae: Hymenoptera) was obtained from the Central Plantation Crops Research Institute (CPCRI), Kayankulam, Kerala District and were maintained in the Biocontrol Laboratory, Department of Agricultural Entomology, Tamil Nadu Agricultural University (TNAU), Coimbatore following the procedures adopted by Jhansi (1984)
Summary
Okra (Abelmoschus esculentus (L.) Moench) which belongs to Family Malvaceae is one of the important vegetable crops grown throughout the tropical and warm temperate regions of the world. Okra is cultivated in an area of 0.78 million ha producing 4.99 million MT with an average yield of 6.39 t ha-1 (Gopalakrishnan, 2007). In India, it is cultivated in an area of 0.31 million ha producing 3.65 million MT with an average yield of 9.59 t ha-1 (FAO, 2007). Earias vittella Fabricius and Earias insulana Boisdual in the later stages of crop growth causes extensive damage to fruits resulting in 69% yield loss (Atwal and Singh, 1990). Its infestation affects the quality and quantity of fruit production, which reduce the market price. Both E. vittella and H. armigera causes up to 50% loss in okra in different parts of the country (Mani et al, 2005)
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