Nematodes are naturally occurring soil invertebrates. There are many species of these small unsegmented worms, some which attack plants, and others that are parasites of insects. It is this latter type that is now being utilized as a form of biological control against a wide-range of insect pests, such as larvae of the asparagus beetles, carrot weevils, Colorado potato beetles, cucumber beetles, flea Beetles, Japanese beetles, June beetles (white grubs), strawberry root weevils, and various tree and vine borers. The effectiveness of nematodes against target pests is due to a symbiotic bacterium that is released from the nematode after the nematodes penetrate into the insect body. The bacteria then multiply rapidly and cause insect death.
Advantages to the use of beneficial nematodes is that they are lethal to many important soil insect pests, yet do not harm beneficial organisms such as lady beetles and earthworms. Their effectiveness, which is dependent upon local environmental and soil conditions, can be quite rapid, usually killing insects within 24-48 hours. On the downside, the use of beneficial nematodes requires knowledge of the susceptible stage of the target insect. In addition, beneficial nematodes require specific conditions to be effective and must be stored and applied properly. Usually, several applications of nematodes are usually more effective than one.
Beneficial nematodes are not required to be registered for use in Canada by the Pest Management Regulatory Agency.
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