Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

_____________________________________________________________________Ecology of insect pests and natural enemies4.11.7 Use of biopesticidesBiopesticides, biological pesticides, biocontrol agents, or microbials, are pesticides that contain a livingorganism or virus as “active ingredient”. Examples are preparations of Bacillus thuringiensis (Bt) andnuclear polyhedrosis virus (NPV). Biopesticides are described in chapter 6 on natural enemies ofeggplant insect pests and in chapter 7 (section 7.10) on antagonists.Another classification of pesticides is “biorationals”. These are pesticides that include biopesticides, butalso chemical pesticides often with naturally occurring biochemicals, such as pheromones and growthregulators. See box below.The Rationale of Biorationals….Insecticides may be divided into two broad categories: (a) conventional or chemical and (b)biorational.Conventional or chemical insecticides are those having a broad spectrum of activity and being moredetrimental to natural enemies. In contrast, insecticides that are more selective because they aremost effective against insects with certain feeding habits, at certain life stages, or within certaintaxonomic groups, are referred to as “biorational” pesticides. These are also known as “least toxic”pesticides.Because the biorationals are generally less toxic and more selective, they are generally less harmfulto natural enemies and the environment. Biorational insecticides include the microbial-basedinsecticides such as the Bacillus thuringiensis products, chemicals such as pheromones that modifyinsect behavior, insect growth regulators, and insecticidal soaps.4.11.8 Use of chemical pesticidesIf all other integrated pest management tactics are unable to keep aninsect pest population low, then use of an insecticide to control the pestand prevent economic loss may be justified. They can be relativelycheap, widely available, and are easy to apply, fast-acting, and in mostinstances can be relied on to control the pest(s). Because insecticidescan be formulated as liquids, powders, aerosols, dusts, granules, baits,and slow-release forms, they are very versatile.Types of pesticidesInsecticides are classified in several ways, and it is important to befamiliar with these classifications so that the choice of an insecticide isbased on more than simply how well it controls the pest.When classified by mode of action, insecticides are referred to asstomach poisons (those that must be ingested), contact poisons, or fumigants.The most precise method of classifying insecticides is by their active ingredient (toxic component).According to this method the major classes of insecticides are the organophosphates, chlorinatedhydrocarbons, carbamates, and pyrethroids. Others in this classification system include the biologicals(or microbials), botanicals, oils, and fumigants.Very often, pesticides are grouped into systemic or non-systemic products. Systemic pesticides aretaken up by plants through the roots, stems or leaves. Once inside the plant, systemic pesticides movethrough the plant’s vascular system to other untreated parts of the plant. Systemic pesticides can beeffective against sucking, boring and mining insects and nematodes.Non-systemic pesticides are not taken up by the plant but form a layer on the sprayed insects or on plantparts.65Eggplant Ecological Guide