Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

__________________________________________________________________________________Major Eggplant Insect PestsNatural enemiesThe little wasp Pediobius foveolatus has frequently been reported to be an effective parasitoid ofEpilachna beetles on eggplant. It has been recorded in countries like India, Bangladesh, China, andJapan. P. foveolatus can attack both larvae and pupae but it prefers pupae and late instar larvae. Insome western countries like USA this parasitoid is commercially available.In a Farmers’ Field School in Roghurampur, Mymensingh, Bangladesh, 96% control of Epilachna beetleby the parasitoid Pediobius foveolatus was obtained in the unsprayed field in studies in 1998.Over 80% parasitism of Epilachna was found in homestead gardens in Jessore, Bangladesh in 1998(pers.comm. P. Kumar, 2001).In a TOT field at Daulatpur, Khulna, Bangladesh, parasitism of Epilachna by Pediobius foveolatus was(pers.comm.Md. Atiur Rahman, 2001):Epilachna pupae: 34%Eggs 41%Grubs 37%Epilachna biocontrol: another success storyEpilachna philippinensis became a serious pest of solanaceous crops on Saipan, Mariana Islands,after its accidental introduction in 1948. In 1985, Pediobius foveolatus was released into heavilyinfested mixed plantings of eggplant and tomato. By 1989, the parasitoid was reared from 80% of E.philippinensis larvae collected and insecticide applications are now only needed occasionally. Rapidsuccess of the programme may be due to an abundance of solanaceous weeds providing anuntreated refuge for parasitoid production (Chiu, 1993).A species of the wasp Tetrastichus was found parasitizing larvae of Epilachna vigintioctopunctata oneggplant in Himachal Pradesh, India, during August 1989. This species was also reported as an eggparasitoid of Epilachna vigintioctopunctata from Indonesia.Management and control practicesAll stages of the insect are exposed on the plants and may be handpicked. Cultivars Arka Shirish, HissarSelection 14 and Shankar Vijay were reported to resist damage of Epilachna beetle, especially E.vigintioctopunctata.Prevention activities:• Use resistant or tolerant varieties where available. For example, the Indian eggplant varieties Makra,Altapati, Gourkajli, Brinjal 72, Puni, and Chicon Long were relatively resistant to the pest(Gangopadhyay, 1997). See table in section 3.2.2. for other examples.• Grow a healthy crop: strong plants are better able to compensate for loss of leaves. See section 4.5.• Sanitation: remove plant debris from a previous crop completely to reduce beetle population. Thismay reduce early attack of a new crop.Once Epilachna beetle is present in the field:• When the attack is moderate or on a limited area, hand-picking of the egg masses and insects andpinching them or destroying them outside the field is a cheap means of control.• Insecticides can kill larvae and adult beetles. As was demonstrated in studies from India, it should benoted that most insecticides, including endosulfan, carbaryl and especially the synthetic pyrethroidsdeltamethrin (decamethrin), cypermethrin, fenvalerate and permethrin are toxic to the parasitoidPediobius foveolatus, causing up to 98% parasite mortality inside host larvae.Points to remember about Epilachna beetle:1. Epilachna beetle eats leaves of many vegetable crops.2. Crops can compensate for leaf damage by producing more leaves. See crop compensationsection 4.5.3. The parasitoid Pediobius sp. occurs naturally in some areas and can reach high control level iffields are not treated with pesticides.4. Handpicking and destroying eggs, grubs, and beetles in small-size fields helps to reduceEpilachna populations.78Eggplant Ecological Guide