Beneficial organisms

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Biology:  Beneficial organisms commonly found attacking insect pests of vegetables include pathogens (diseases that affect insects) (Photos 176 and 177), parasitic and predatory insects.  Among the most important pathogens are fungi which attack aphids.  Epizootics often occur and result in complete decline of the pest population (Photo 178).  Parasitic insects typically insert an egg into the host insect and the parasitic larvae develops within the host and causes death (Photos 179 and 180).  Predatory insects are typically larger than their prey.  Examples include larval (Photo 181)and adult (Photo 182) ladybeetles, syrphid larvae (Photo 183), robber flies (Photo 184), predatory beetles and many others (Photos 185 and 186).

Management:  Beneficial organisms naturally occur wherever vegetables are grown and efforts at conserving them is one of the principal strategies of IPM programs.  Synthetic broad spectrum insecticides are highly detrimental to beneficial insects.  Avoiding or delaying the use of these insecticides will greatly enhance the role of beneficial insects.  With many insect pests, especially lepidopterous larvae, use of Bacillus thuringiensis may provide acceptable levels of control and will conserve the beneficial insects. 

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