Chapter 26

Integrated Pest Management in Greenhouses

Biorational Pest Control in Greenhouses

Unlike conventional synthetic pesticides as discussed in the next section, which are classified on the basis of their chemistry, biorational pesticides are grouped on the basis of some shared characteristics. Biorationals are often referred to as “Soft” or “reduced-risk” pesticides. For example, they pose minimal to no risk to the environment due to their chemical make-up, rapid degradation, or the small amounts required to effect control. Biorational pesticides vary in their toxicity and in their potential ecological impact. Biorationals in general have a narrow target range and a very specific mode of action. They are slow acting, have a relatively critical application times, suppress, rather than eliminate a pest population. In addition, they have limited field persistence and a shorter shelf life than conventional synthetic pesticides and present no residue problems. Most biorationals are better suited to use as preventative rather than curative treatments.

Biopesticides

Biopesticides, as defined by the Environmental Protection Agency (EPA), are certain types of pesticides derived from such natural materials as animals, plants, bacteria, and certain minerals. Categories of biopesticides include: (1) biochemical pesticides, which are naturally occurring substances that control pests by non-toxic mechanisms, such as sex pheromones that interfere with mating and scented plant extracts that attract insect pests to traps; (2) microbial pesticides, which consist of a microorganism (e.g., a bacterium, fungus, virus or protozoan) as the active ingredient; and (3) Plant-Incorporated-Protectants (PIPs), in which pesticidal substances are produced by crop plants as a result of genetic material being added to the plant (e.g., Bt insecticidal protein). With plant-incorporated protectants, the toxin and its genetic material, but not the plant itself, are regulated by EPA.

Biorationals Approved for Organic Crop Production

Most biorationals are approved for organic crop production, thus they are a logical fit for managing pests in organic crops. However, some formulations are not approved, which can be due to inert materials or synthetic additives. Some biorationals are not allowed under National Organic Program (NOP), for example phosphorus acids and genetically engineered PIPs.

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