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Beating Pests with Plant Chemicals

It would seem that landscapes are filled with pests ready to devour our favorite plants. We can often see evidence of pest damage in the form of leaf curls, stippled leaves, or chewed holes in foliage. How do plants survive with all the pest threats without intervention from people?

Many plants have their own alert system to help manage a plant-feeding insect attack. When tissues are damaged by plant feeders, the plant releases volatile chemicals that serve as signals for many beneficial insects. Predators such as lady beetles, lacewings, and predatory bugs ‘pick up’ the chemical signals and fly to the injured plants to find their prey.

Ladybeetle larvae will eat many soft-bodied pests.

Ladybeetle larvae will eat many soft-bodied pests.

An interesting part of this occurrence is that the release of chemicals by one plant can stimulate other surrounding plants to build up their chemical defenses against future pest feeding.

The key lesson for all gardeners is that there are many natural processes going on without our knowledge. Instead of immediately applying a broad-spectrum insecticide at the earliest sign of pest feeding on a plant, give the predators a chance to provide you with a free and environmentally sound form of pest control.

One Comment on “Beating Pests with Plant Chemicals

  1. Dear Beth,

    Your articles are always inspiring.

    This one has a little different slant on the pest as we normally think about. This is a wonderfully surprising article in a very small amount of space. I believe that those that are not Master Gardeners will also be amazed.

    Would you give me permission to include this article in the next FFGC District 1 Newsletter?
    You will get all the credit of course.

    If it is not alright, I’ll understand.
    Thank you,