Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

__________________________________________________________________________________Major Eggplant Insect PestsWhiteflies also excrete honeydew, a sweet sticky fluid which may cover the leaves completely. On thishoneydew, mould fungi grow and the leaves may turn black in color. This reduces the capability of theleaves to produce energy from (sun)light (photosynthesis) and may lower fruit quality.In some hosts, damage can result from whitefly feeding toxins that cause plant disorders such asirregular ripening of tomato. Plant viruses also can be transmitted by whiteflies, such as leaf curl intomatoes. Plant disorders and virus transmission are of particular concern because they can occur evenwhen a whitefly population is small. There are no records of any virus transmission by whiteflies ineggplant.Natural enemiesThere can be many indigenous natural enemies of whiteflies in your area.Natural enemies of whitefly, to name but a few….Studies carried out between 1985 and 1987 in Andhra Pradesh, India, on cotton showed theoccurrence of nymphal parasitism of whitefly due to the parasitoid wasps Eretmocerus serius,Eretmocerus sp. and an unidentified parasitoid wasp. Populations of predators included thecoccinellids Brumoides suturalis, Verania vincta, Menochilus sexmaculatus, Chrysoperla carnea, andthe predatory mite Amblyseius sp. Fungal pathogens found included Aspergillus sp., Paecilomycessp. and Fusarium sp. (Natarajan, 1990)• predatorsWhiteflies are controlled by predatory insects such as green lacewing (Chrysopa sp.) orladybeetles (Coccinellidae).The predatory bug Macrolophus caliginosus is another known predator of whitefly and toa lesser extent spider mites, aphids, moth eggs, leafminer larvae and thrips. Bugpopulations develop most rapidly on whitefly. Adult bugs can also survive for some time ladybeetleon plant saps. In countries like the U.S.A. Macrolophus is a commercially availablenatural enemy. It is successfully released in greenhouse environments. Whether this bug occursnaturally in the tropics and how effective it is needs to be studied.• parasitoidsWhiteflies can be controlled by parasitic wasps such as Encarsia or Eretmocerus species.Parasitism can be quantified by counting the number of empty whitefly pupal cases with a circular exithole (created by the emerging adult wasp) rather than a “T” shaped split (created by the normal adultwhitefly emergence).Numbers and activity of whitefly parasites and predators can be encouraged by avoiding broad-spectruminsecticides, planting of refuge crops, and, in some areas, augmentative releases.• pathogensWhiteflies can be controlled by fungal diseases such as Beauveria, Paecilomyces or Verticillium species.These fungi often occur naturally.Whitefly mortality from pathogenic fungi often reaches high levels in greenhouseswhere relative humidity is constantly high and spores naturally accumulate.Pathogenic fungi can be applied as a spray treatment and are effective at anypopulation density. Insect pathogens used for whitefly control must be applied withgood coverage and under proper environmental conditions (high relative humidity) tobe effective. The fungus Verticillium lecanii is commercially available in Europe for thecontrol of greenhouse whitefly. Other products are being tested in commercialproduction fields and greenhouses, but the economic feasibility of their use has yet tobe determined.pathogen sporesAnother fungus, Peacilomyces fumosoroseus, is also commercially available for whitefly control. It canbe applied as a spore solution and it has some activity against aphids, thrips and spider mites.92Eggplant Ecological Guide