Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

__________________________________________________________________________________Major Eggplant Insect Pests• Small populations can also be removed by picking the infested leaves by hand and destroying these.• When large populations of aphids are present in the field at an early stage (newly transplanted oryoung plants) and the weather is warm and dry, chances are that the aphid population will expandvery quickly. Monitor the field closely for presence of natural enemies (particularly ladybeetles, andaphid “mummies” and in wet season: fungi (see chapter 6)). When there are large numbers of naturalenemies, do not apply insecticides but continue monitoring. When natural enemy populations are lowcompared to the aphid population, and removal by hand is not feasible, consider localized sprays.See next point.• There are insecticides that control aphids. However, insecticides can kill ladybeetles and many othernatural enemies of aphids and other pest insects! Balance the benefits of spraying against the harmdone to the beneficials! When applying insecticides is considered necessary, apply only on thoseplants that have aphid colonies, not on all plants. This reduces the amount of pesticides needed andmay save at least part of the beneficials present in the field.• Some botanical extracts are reported to control eggplant aphids. For example, an extract oflemongrass prepared by grinding 10 g of green leaf in 1 liter water caused reduction in aphidpopulation in trials in India (Asari, 1974). Neem kernel oil is another botanical regularly used foraphid control. It should be noted that botanicals may also destroy natural enemies. This can betested in an insect zoo. See box in section 4.9.Points to remember about aphids:1. Good crop sanitation, healthy plants, intercropping, and use of reflecting mulches may all helpprevent or delay aphid infestation.2. Aphids have many natural enemies, e.g. ladybeetles, hoverfly larvae, several parasitoid species, andfungi (in the wet season).3. Aphids can be controlled by hand rubbing, application of botanicals, or spot application ofinsecticides (only when infestation is severe at early vegetative growth stages), and they can bewashed off with water or soap solutions.Related exercises from CABI Bioscience/FAO Vegetable IPM Exercise Manual4-D.1. Predation on sucking insects in insect zoo4-D.2. Cage exclusion of natural enemies in the field4-D.3. Screen caging in nursery4-D.6. Use of light reflective mulch to manage thrips and/or aphids5.6 Thrips - Thrips sp.See photos 12, 13 (page 176).Various species, most commonly Thrips tabaci and Thrips palmi.DescriptionThe adult thrips is a very small insect, about 1 mm long, brownish-yellowin color with two pairs of long, narrow wings (the fore-wings are longerthan the hind wings), both pairs of which are fringed around their edgeswith hair-like structures. The nymphs are pale yellow, almost transparentwhen newly hatched, and similar to the adults but smaller and wingless.There is a “pre-pupal” stage which is white in color with short wingsheathsand antennae which are held straight in front of the head. The“real” pupa is about 1 mm long and brownish in color.Thrips adultThrips are gregarious insects and large numbers are often found together on single leaves.86Eggplant Ecological Guide