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Super Duper Beetle Scooper and other pest management tactics

July 24, 2008

Aphids on tomato flowers

Following Josh’s recent post about pest management in the Sebastopol energy gardens I thought I would share some of the strategies and tactics we use for pest management on the Kentucky State University organic land.

In the fall of 2006 we had a terrible aphid infestation in our high tunnel (right). It was the end of our first production season in the tunnel, and I was embarrassed by how bad it looked. We tried, unsuccessfully, to keep the aphids in check with occasional applications of Safer Insecticidal Soap (pdf of label), which kills soft-bodied insects through desication by dissolving their waxy cuticle. It wasn’t enough.

A range of beneficial insects eventually found our aphids, and brought them under control naturally. We have wasps that lay their eggs inside aphids, leaving their larvae to consume the ‘aphid mummies’ from the inside out. We have flies that lay their eggs near aphid clusters, leaving voracious, aphid-eating maggots. We have charismatic lady beetles and lacewings. We try to keep these beneficial insects around by providing nectar sources and varied habitat. We haven’t had an aphid problem since.

When I worked as a pest management consultant in large greenhouses in southern British Columbia, I would recommend weekly releases of these beneficial species, plus other predators and parasitoids to keep whiteflies, spider mites, thrips, and other insect pests in check. Bringing in beneficial insects by mail order wouldn’t be economical for our little high tunnel, but we don’t need to introduce them if we can simply encourage the locals to establish themselves.

Parasitized tomato hornwormTomato hornworms (left) cause occasional problems, but we have a strong population of wasps that parasitize the caterpillars. I rarely see a hornworm that isn’t covered with wasps’ caccoons, which ensure its impending demise.

If caterpillars get ahead of our beneficials we occasionally apply a bacterium called ‘Bacillus thuringiensis var. kurstaki’ or ‘Btk.’ It causes a disease that only kills leaf-feeding caterpillars. Btk is probably the most commonly-used biological insecticide on organic farms.

This week we applied a mix of Btk and vegetable oil to the browning silks of our sweet corn in an attempt to prevent corn earworm problems. On-farm research conducted in Iowa has shown this labor-intensive practice (each ear is treated individually) can be effective when corn earworm pressure is high. This is the first year we’ve tried it, so we won’t know whether it worked for a while.

Leaf-feeding beetles give us some headaches. The worst among these are flea beetles on our brassicas and eggplants; Colorado potato beetles on our potatoes and tomatoes; and cucumber beetles on our cucumbers and squash.

Row covers (below) work well to exclude these beetles, and to protect crops
from early spring frosts, but they have to come off before flowering to
allow pollination of the fruiting crops.

Row covers

Super Duper Beetle ScooperHand-picking is possible for small areas infested with Colorado potato beetle, which is a relatively large, slow-moving insect. It’s almost impossible for smaller, faster beetles like flea beetles and cucumber beetles.

A market gardener a few miles from here has invented a device he calls a ‘Super Duper Beetle Scooper’ (right) to make make hand-picking beetles and other insects easier. I visited his farm last week, and collected some video footage of the inventor, Ken Waters, using his tool.

Ken makes his scoopers out of used 2-liter pop bottles and jars. The best way to figure out how to make one yourself is probably to buy a sample from Ken on ebay for $10.

Row covers and beetle scoopers are both forms of ‘physical control’; fences are another. I have had success using fences to exclude slugs, root weevils, and cabbage flies. Fences are also our first line of defence against deer, which can cause more damage more quickly than any of the insect pests on our farm.

Deer love our sweet potato tops and our edamame soybeans. Last year we erected wire mesh fences (left) to protect our small sweet potato plots from deer. This year we have solar-powered strands of electric wire (below) around our energy farms plots to discourage deer.

Fence around sweet potato

Solar electric fence

Michael Bomford provides research and extension services related to organic agriculture and small-scale renewable energy production through Kentucky State University’s Land Grant Program. All photos and video in this post are by Michael Bomford.

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