Belle of Dirt

Missouri Ozarks mom, mover of earth, photographer, maker and plant enthusiast


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Blister Beetle Battle

My daughter and I have been SO proud of our cherry tomato plants that we grew from seed this spring; we nursed them in sunny windows until they were fledgling plants big enough for the garden. All through the past couple months we have mulched, fed and watered them, excited and accomplished when the first blossoms emerged, turned to green fruits and then to red. We look forward each day to going out in the yard and picking our little cherries.

Blister beetle noshing a leaf

I first spotted a couple of beetles yesterday morning while watering. Since there were only two, I hand-picked them off the plants and squashed them under a boot, then went about my business. Where the beetles had been eating, there were some black flaky looking bits of stuff, but they sprayed off easily with the garden hose.

Next afternoon, we were out working on building our new deck and I checked our plants for ready tomatoes as usual. I was horrified to discover that our plants were now COVERED in striped beetles, noshing away on the leaves until they looked like lace. They’d started from the bottom and made rapid work towards the top, leaving little but green fruits and stems.
I panicked.

In spite of years growing ornamentals, countless trees, shrubs and flowers, this is my first year with a vegetable garden. In the past, I liberally used chemical fertilizers, weed controls and pesticides in my yard to control whatever ailment my plants suffered, whether fungus, insect damage or other. One season I lost over half the plants I’d worked so diligently to grow for two years from a Weed and Feed fertilizer that I either applied too liberally or the chemical was simply too harsh for what I was trying to grow.

Until this week, when faced with a blister beetle battle, my chemical use had been almost non-existent for several years. Compost and lawn clippings, kitchen scraps, manure and leaves were my fertilizers. The pond next to the garden attracted frogs and birds to help prevent pests on the ornamentals. Recycled milk and cat litter jugs served as slow-watering systems, rather than buying many feet of soaker hose or sprinklers.
There was a bag of Sevin dust sitting in the back of the cabinet; had been there for at least 5 years or so, unopened. Faced with all that cherry tomato destruction (I swear I could HEAR them chomping away), I ran in, grabbed the Sevin dust and threw liberal handfuls all over the plants. I watched with great satisfaction as those chewing little buggers began dropping off, writhing and squirming. I hoped in vengeance of my plants that they were suffering greatly.

It occurred to me following this rash dumping of handfuls of poisonous dust all over my garden that I had done just that; next to the frog pond and all over the food we intended to eat. I decided I’d try to minimize the spread of the poison to the pond water and hosed everything down liberally the next morning until the water ran clear into the yard. I’m hoping it didn’t leach much into the pond water and won’t hurt my frogs in the long run. We’ll be carefully washing anything we eat off of those plants for a while. L

Beetle Blisters

The articles on the internet about these beetles did little, if anything to make me feel better about their being in my garden, after seeing pictures of the damage they could cause to both plant and human skin. The Striped Blister Beetle produces a substance called cantharadin that causes horrible blisters on skin; it is also toxic to animals. An article from Texas A & M Entomology claimed that a horse could be killed by ingesting only 2 or more of the beetles, even if the beetles were dead.  Farmers have had trouble with attacks on their alfalfa crops and the beetles in turn, winding up in livestock feed.

The beetles look very similar to a lightning bug; they are about the same size and shape, but with very distinctive stripe patterns on their backs. They lay their eggs in cells just beneath the soil surface. Adult beetles eat foliage and fruit, while the larvae are said to feed on grasshopper eggs. (This was the ONLY beneficial fact I could find about them)

Several blogs and forums I read stated that people had minimal success with hand picking (be sure to wear gloves!) and dropping them into a container of soapy water. Most complained that there were SO MANY by the time they noticed them that this was impossible without using a vacuum cleaner to do the job.
A couple people mentioned a homemade spray made up of organic dish soap, canola oil, 2 cloves of garlic and red pepper flakes strained into a tea as an was effective method of getting rid of them. They did mention that this spray, while safe on vegetables (wash before eating of course) for human consumption, seemed to kill beneficial pollinators such as bees and butterflies as well. Some suggested protecting plants with mosquito netting. This of course only works if you get to the plants before they are infested with the little monsters.

I can say from my own experience that the Sevin dust worked to kill them beautifully, but there’s no telling what else it killed before I washed it off. There were quite a few dead daddy long legs hanging off the plants when I rinsed them the next morning. If I happen to get unlucky with another visiting swarm, I’ll head to the grocery store and try some of the organic spray I mentioned above instead.

Any of you had to fight the blister beetle battle? What did you use to get the little buggers to move on?

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