How to Rid Your Garden of Corn Borers
Corn borers don't just attack corn. They also like peppers, potatoes, tomatoes, beans and onions. Fortunately, there are beneficial insects that love dining on corn borers wherever they are found in your garden.
Know your enemy
The corn borers that we find in our gardens are European Corn Borers. They are not native to North America. They were brought here, unintentionally, prior to 1917 in broom corn which was imported to make brooms.
Corn borers overwinter in the plant debris in your garden. They hatch into pale brown moths with zigzag markings in June. The female moths lay eggs from the end of June to the middle of July in clusters of 15 to 20 on the undersides of leaves. The eggs hatch within a week and the larvae feed for an additional three to four weeks. The young larvae feed on leaves, tassels and under the husks while older larvae burrow into the stalks of your corn or the stems of your other crops.
Once burrowed into the stalks and stems, the larvae pupate and hatch into a second generation of moths which begin the cycle again. In warm climates it is possible to have up to three generations in one growing season.
Squeeze 'em til they scream
If you find a corn borer larvae burrowing into the stalk of your corn or the stem of one of its other favorite crops, you can kill it by squeezing the stalk. No fuss, no muss.
The enemy of my enemy is my friend
There are a number of beneficial insects that eat corn borer eggs and larvae including lacewing larvae and trichogramma wasps. Invite them into your garden by planting their favorite herbs and flowers. Specifically, they like plants that have tiny flowers such as yarrow, dill, fennel and mint.
Buy some friends
Lady bugs love corn borer eggs and can eat up to 60 eggs per day. If you don't already have lady bugs in your garden, you can buy them through mail order and release in your garden where they will gorge themselves on corn borer eggs and the aphids on your roses. Just bear in mind that when they have eaten all of the available food, they will fly away in search of more. They don't stick around.
Bt, not btw
Bt, or Bacillus thurengiensis, is a naturally occurring bacteria that is found in most organic pesticides. It infects and kills the corn borer larvae that is burrowing into the stalks and stems of your crops. Bt is safe for use on food crops.
Cleanliness is king
Prevention is always preferable to control of garden pests. Clear away all plants and weeds in the fall and then till your garden. This robs the borers of places to overwinter and the tilling kills any that are left.
More on garden pests
© 2014 Caren White
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