Safe insect use for pest control

Asked June 7, 2015, 11:14 AM EDT

I saw online the use of praying mantis to control pests like aphids and such. Is this safe? Is there a list I can use to identify good insects to introduce and cultivate in my garden in Milwaukie oregon?

Clackamas County Oregon biological control horticulture

1 Response

Is a praying mantis a safe option for pest control?

Yes praying mantises are completely safe to use as a pest predator in the garden. They can bite but usually don't and apparently it doesn't hurt anyway (I've never been bitten by one).

It's best to buy an egg sack that will produce hundreds of baby mantises. And also try to contain them in one area, such as a greenhouse or poly tunnel. If you can't contain them they will likely just migrate to another place where there is more food and less competition. They can fly.

It may be better to do the following:

  • Introduce or encourage natural aphid predators. Avoid the use of broad spectrum pesticides which kill aphid predators such as ladybugs and green lacewings. Do not purchase adult ladybird beetles, as they tend to disperse on release. A better predator to purchase may be the green lacewing, available for sale as eggs or larvae.
  • The best strategy is to grow plants that attract and foster natural predators. These include yarrow, wild buckwheat, white sweet clover, tansy, sweet fennel, sweet alyssum, spearmint, Queen Anne's lace, hairy vetch, flowering buckwheat, crimson clover, cowpeas, common knotweed and caraway.
    If the above strategies just don't seem to do the trick, try the least toxic method of chemical control of aphids - commercial insecticidal soaps. These soaps, available at most lawn and garden stores, eliminate only the insects that come in direct contact with the soap.
Thanks for your interesting question.