Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

__________________________________________________________________Major Natural Enemies of Eggplant Insect PestsA female can lay 200 to more than 1000 eggs over several months. The more food there is, the moreeggs it lays. That way, it can keep up with the pest insect populations. Eggs are usually deposited nearprey such as aphids, often in small clusters in protected sites on leaves and stems. The eggs are small(about 1 mm), cream, yellow or orange in color.The last larval instar pupates attached to a leaf or other surface. Pupae may be dark or yellow-orange incolor. Pupal stage takes about 3 to 12 days, depending on temperature and species. Adults live for a fewmonths up to a year and have several generations in a year.EffectivenessLadybeetles are voracious feeders. As an adult, they may eat as many as 50aphids per day. Each larva eats 200 to 300 aphids as it grows. They are effectivepredators when the pest population is high: one adult may eliminate all aphids froma seriously infested plant in just a few days. Ladybeetles are thought to be lesseffective when pest densities are low. There may also be some crop damagebefore ladybeetles have an impact on an aphid population.Because of their ability to survive on other prey or on pollen when there are not somany aphids, ladybeetles are very valuable.Ladybeetle larvaeating an aphidIn Thailand, at Regional Institutes of Biological Agriculture and Farmers’ Field Schools, ladybeetles arereared and available to farmers for field releases.ConservationLike many other natural enemies, ladybeetles are easily killed by broad-spectrum insecticides. Avoid theuse of these pesticides as much as possible!Ladybeetles benefit from shelter for protection from adverse weather conditions and for refuge whencrops are harvested. This shelter can simply be some plants around the field.6.1.2 Ground beetles - CarabidaePrimary prey: soil-dwelling beetles and fly eggs, larvae, pupae, other insect eggs, small larvae and softbodiedinsects, some caterpillars.Predatory stages: both adults and larvae are predators.Description and life cycleThere are many species of ground beetles. Adult ground beetles may be very small(about 3 mm) to large (12 - 25 mm). Many are dark, shiny beetles, often withprominent eyes and threadlike antennae. Adult ground beetles are found understones and left-overs and they are active mainly at night. They can run rapidlywhen disturbed or when in search of prey. Night-active species are black. Thosethat are active during the day may be brightly colored or metallic in appearance.Eggs are usually laid singly on or in the soil near prey, sometimes in speciallyconstructed cells of mud or twigs. The eggs can be soft, cylindrical with roundedends and about 0.5 mm long. Some species lay only a few eggs, others may layhundreds of eggs. Generally, the more food there is for a ground beetle, the moreeggs it lays. That way, it can keep up with the pest insect populations.ground beetleThe larvae usually have large heads with large jaws for holding and piercing prey. They look verydifferent from the adults. Most species pupate in the soil.You can catch ground beetles with pitfall traps in the field. See section 4.11.2.EffectivenessThe larvae and adults of several ground beetle species have been shown to eat many prey if given theopportunity. There is little field data on the efficacy of ground beetles. Their ability to cover largedistances in search of prey makes them a valuable addition to other natural enemies.98Eggplant Ecological Guide