Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

__________________________________________________________________Major Natural Enemies of Eggplant Insect PestsCeranisus menes has been reported from various other countries such as India, Taiwan, and Italy,Spain, Benin (Africa), and USA. Ceranisus has been found in association with larval populations of thethrips F. occidentalis and other thrips species in several crops.Strains of C. menes collected worldwide are different in biology and behavior, according to theirphenotype and geographical origin. There are strains with yellow and with brown abdomen. Yellowstrains were generally more effective, produced more offspring but showed a greater variation indevelopment time than brown strains. As host (thrips) size increased, fewer larvae were attacked andparasitized successfully (Loomans, 1995).Parasitoid development and reproduction depended on temperature. Under laboratory conditions, thedevelopment of this parasitoid took 23-30 days at 25°C and 28-34 days at 20°C. Temperatures above29°C increased mortality of the parasitoid. Development was synchronized with larval development of thehost. In rearing units, 35-105 hosts were parasitized per female (Loomans, 1991).More study is needed to investigate effectiveness of this beneficial wasp under field conditions in SEAsia.6.2.6 Trichogramma speciesTrichogramma wasps are usually well-known because there are so many members thatare important natural enemies of agricultural pests. Most of them have a wide hostrange, especially among the moths. Some of the important Trichogramma wasps are:• Trichogramma chilonis: parasitoid of borer insects such as tomato fruitworm(Heliothis armigera), corn borer (Ostrinia nubilalis), eggplant fruit and shoot borer(Leucinodes orbonalis).• Trichogramma japonicum: parasitoid of eggplant fruit and shoot borer (Leucinodes Trichogrammaorbonalis).• Trichogramma evanescens: parasitoid of the cabbage moth (Mamestra brassicae).• Trichogramma ostriniae: parasitoid of corn borer (Ostrinia nubilalis), corn earworm (Heliothisarmigera), cabbage looper (Plusia sp.), and diamondback moth (Plutella xylostella).• Trichogramma pretiosum: parasitoid of many vegetable insect pests.• Trichogramma nubilale: parasitoid of the European corn borer (Ostrinia nubilalis).Several species have been mass-reared for use in biological control programs. In some countries,Trichogramma wasps are commercially available often subsidized by the government. They may also beavailable from research institutes for trial purposes.For example in field trials in the Philippines, several species of Trichogramma were evaluated for controlof fruit and shoot borer of eggplant (Leucinodes orbonalis). T. chilonis gave the highest parasitism. T.chilonis is mass-produced in the Philippines by both government and private sector to control manylepidopterous pests, especially borers such as corn borer, tomato fruitworm, cacao pod borer, sugarcane borer, and rice stem borers. Trichogramma pupae are glued to cards (“Trichocards”) and clipped toplant parts at several locations in the field (FAO – Dalat report (V. Justo), 1998).Description and life cycleTrichogramma wasps are all egg parasitoids. The adult wasps arevery small, mostly less than 0.5 mm! Most people have never seen theadults: you need a good lens to even spot them. The presence of thewasps is usually recognized by the parasitized egg masses. Theadults are often yellow or yellow and black in color, with bright redeyes, short antennae and a compact body.A female wasp lays one or more eggs in an egg of the host insect, andone or more parasitoids develop. Trichogramma wasps pupate insidethe host egg. Eggs usually turn black as the parasitoid developsinside. A small hole in the black host egg indicates that the wasp hasemerged.Female Trichogramma wasplays eggs in host eggDevelopment of the parasitoid is favored by warm temperatures and many generations may be producedeach season.108Eggplant Ecological Guide