Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

__________________________________________________________________Major Natural Enemies of Eggplant Insect Pests6.2.3 Pediobius foveolatusHost: Epilachna beetle – larvae and pupae.This little wasp is a parasitoid of various Epilachna beetle species, including the Mexican bean beetle,Epilachna varivestis. It is native to India and China, and has been recorded in Bangladesh, Japan, HongKong. Possibly it occurs in other countries in Asia as well. It has been successfully released for examplein Mariana Islands for the control of the Philippine ladybeetle, Epilachna philippinensis, on tomato andeggplant (Chiu, 1993). See box in section 5.2.The parasitoid is able to parasitize all larval stages of the Epilachna beetle but prefers later instars.Parasitized larvae change color from yellow (unparasitized) to tan – brown. This color change is verydistinct and can be easily recognized in the field. Parasitized larvae can be found at the underside ofleaves and are very firmly attached to the leaf surface.Peak incidence of the parasitoid on eggplant in India occurred in June at locations Hoskote (South India)and October in Hebbal and Kengeri. In Bangladesh, peaks were reported in July – August. The timetaken by the parasitoid to complete one generation was 11-17 days during September-October and 10-13 days during March-April.Pediobius foveolatus parasitized 3.3-62.0% of the larvae of the coccinellid Epilachna ocellata collectedfrom bitter gourd fields during kharif in Madhya Pradesh, India (Dhingra, 1986).Other studies report that the average number of parasitoids emerging from Epilachna larvae underlaboratory conditions was 20.2 and from field-collected larvae was 9.6; an average of 12.4 parasitoidsemerged from parasitized pupae. The life-span of adult male and female parasitoids was 8 and 10 days,respectively (Patalappa, 1979).6.2.4 Tetrastichus sp.Host: Epilachna beetle – eggs, and larvae.Tetrastichus, a wasp, is a parasitoid of Epilachna beetle eggs, and larvae. In a field study during therainy season in Madhya Pradesh, India, the wasp Tetrastichus ovulorum parasitized 19.3-45.5% of theeggs of the coccinellid Epilachna ocellata, collected from bitter gourd fields (Dhingra, 1986).In Sumatra, Indonesia, two species of Tetrastichus were found to parasitize the eggs of Epilachnavigintioctopunctata on eggplant (Nakamura, 1988).Tetrastichus sp. are usually metallic blue-green tiny wasps of 1 – 3 mm long. The adults of some speciesalso feed extensively on beetle eggs, leaving collapsed shells that fall from the plant after several days.More than 50% of the host eggs may be damaged. Several wasp larvae develop in each beetle larva.The majority of parasitized beetle larvae may drop from the foliage to form a pupal cell in the ground.They fail to pupate and ultimately, the adult wasps emerge.A negative point is that species of Tetrastichus have been found to parasitize larvae and pupae of thebeneficial green lacewing Chrysopa carnea, and the beneficial ladybeetle Coccinella septempunctata.6.2.5 Ceranisus menesHost: thripsIn a survey of natural enemies of the thrips species Thrips palmi on eggplant in Thailand, the waspCeranisus menes was found to be the most effective natural enemy. Similarly, Ceranisus menes wasfound on thrips infesting eggplants in Japan (Hirose, 1992). Parasitism by this small wasp was limited tohome gardens which were not sprayed with insecticides (Hirose, 1993).Other researches have found Ceranisus menes to be a parasitoid of other thrips species like Frankliniellaoccidentalis, an important pest of greenhouse vegetables in Europe.107Eggplant Ecological Guide