Structure attracts wasps that prey on cabbage worms
by Alan Detwiler April 12, 2013
Paper wasp next enclosure:
A couple of years ago I noticed a paper wasp carrying the larva of a cabbage worm. Since then I have seen wasp on cabbage and other brassicas apparently searching for cabbage worm catepillars. It occurred to me that it might be worth my while to provide a nesting site for paper wasp near the garden. If a large number of wasps would patrol my garden's brassicas maybe I could spend much less time hand picking the destructive catepillars from the cabbages, cauliflowers, and other brassicas that have in recent years made up an important part of my garden crops.
So last year I nailed together 3 12-foot long 2 by 6s that where otherwise just scrap lumber. The three 2 bys were nailed, basically long edge to long edge forming a 12 foot long channel shape. Two 6 foot locust post put into 24-inch deep holes about 6 feet apart served as supports for the channel which was placed, inverted, atop the post. That formed a protective, partially enclosed space for the wasps to build their comb-like paper nests. A baffle consisting of an approximate 6 by 6 inch piece of 3/4 inch thick board was nailed within the channel near the end of the channel facing the prevailing wind to further protect any nest that wasp might build with the inverted channel.
That was done in July of 2012, late in the wasps nest building season. Only one nest was built and that nest was made within a few inches of the baffle. That suggested that wasp prefer a more enclosed space than the more open other areas of the channel, so about a week ago (early April, 2013) during a warm spell when I saw paper wasps flying, I thought it was time to add more baffles along the inverted channel to prehaps attract a large number of the nest builders this year. I cut about 10 more baffle from 3/4 inch by 4 1/2 inch scrap board and nailed them about every foot inside the inverted channel.
We'll see what happens. Hopefully, I'll get a lot of help this year with controlling the damage to my brassica crops. I'll post to this page again after the current growing seasons ends to report how this strategy succeeded or failed.
The 12-feet long wasp house supported on two 4-foot tall posts.
View from underneath the wasp house, looking upward at one of the ten or so baffles spaced every 12-inches or so along the wasp house.
Contributed by Alan Detwiler. Bio at
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