Organically Controlling Chestnut Weevil

Between the months of April and August, the chestnut weevil makes its appearance. This chestnut-eating and destroying pest has a snout that can be longer than its body. It uses that snout to burr into chestnuts, depositing its eggs that way. But the weevil's destruction can be stopped as late as fall, if you know what to look for and do.

The chestnut weevil, approximately a half-inch in size, attacks Asian chestnuts whereever they are located. It isn't always easy to spot signs of this pest, as they can feed on the chestnut kernal inside for three to five weeks, but leave the nut shell intact. In the state of Kentucky, the lesser-sized chestnut weevil (they have two sizes) emerges between late May and the end of July but eggs are not lain until the fall. The larger chestnut weevil located in that state make their appearance in late July and through August, laying their eggs immediately. Hence, organically controlling chestnut weevils begins in April and goes on through the first part of fall.

Organically Controlling Chestnut Weevil

Having chickens around your chestnut tree can actually help, as they serve to clean up the chestnut weevil larvae. This larvae, which is legless, plump and white is curved in shape like a crescent moon. As the larvae matures it overwinters, approximately 3 to 6-inches below ground, but the chickens can get to it.

If you don't desire to have chickens near your chestnut trees or in your yard, you can also practice another organic remedy: plant your chestnut trees away from any woods or forest in the area. This will reduce the possibility that squirrels or other small animals will bring infested nuts near your tree.

In addition, an one of the simplest organic means of controlling chestnut weevil is to pickup your chestnuts daily from the ground. Check to see if a hole has been made into the side of the nut. If it has, the larvae from the weevil has already dropped to the ground and entered the soil. If not, you can heat the nut to 140 degrees Fahrenheit to kill the potential larvae on the inside, without destroying the nut. Chestnuts will need to stay in the higher temperature water for about 45 minutes in order to kill the weevil larvae.

Falling Chestnuts and Organic Control

While you can't eat these infected nuts which have no hole in the side of them, immersing them in water will at least prohibit the chestnut weevils from entering your tree soil and beginning the infestation process all over again. Chestnuts on the ground with a hole in their side, however, do indicate you have this pest and your soil is now infested too.

Sources:
"The Gardener's A-Z Guide to Growing Food Organically" by Tanya L.K. Denckla
The University of Kentucky College of Agriculture: "Nut Weevils"

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