Tuesday, February 27, 2007

How to get rid of Blister Beetles Organically

I do not believe in using chemical pesticides to rid garden pests. So how do we as organic gardeners get rid of pest insects? There are many ways, but that is not the topic of this post. This post is about my garden's arch enemy: The Blister Beetle!

The blister beetle is usually a problem in alfalfa hay fields, but for some reason, they were especially attracted to my heirloom tomatoes last year!

Perhaps one of the drawbacks to growing heirloom tomatoes is that they are less resistant to disease and to pest insects.

Blister Beetles get their name from the fact that they contain a toxin called cantharidin that will make your skin break out in blisters if you come in contact with it. Usually you would need to touch a crushed beetle to break out, but some people can have an allergic reaction just from touching one of the beetles. The blister beetles in my garden ate a lot of tomato foliage, but the most disgusting part about them was that they left huge droppings behind as well!

Enough already! They disgust me so!

That was way too long of an introduction! This post is supposed to be about what I'm going to do about blister beetles in the garden this year. They bothered me so much last year that I put controlling them high on my 2007 garden to do list. If you look at the list you will see that I plan to grow horseradish next to my heirloom tomatoes to keep away the blister beetles. Where did I get the idea that horseradish would keep them away? From a great book about companion planting:

Carrots Love Tomatoes, by Louise Riotte is the foremost authority on companion planting ideas. Riotte writes in the book that horseradish will keep blister beetles away. Using horseradish root in water as a spray will deter many insects. She goes in to what deters animal pests as well. I am following her advice and growing morning glories on my fence to keep deer away and cucumbers to keep raccoons away. Radishes next to those cucumbers will keep the striped cucumber beetle at bay.

This is a great book because in addition to advice on what to grow to keep pests away, it lists what vegetables and herbs will enhance the growth of others if grown at close proximity. The title tells of one; carrots love tomatoes.

I am planning where to place each vegetable in my garden this year based on these companion planting recommendations, which is number one on my to do list.

So there you have it, number one and two on my list. I hope to be able to write about most of the items on that list.

Thank you for reading this whole post. I apologize for the disgusting beginning. Now you know why I'm determined to be ready for the blister beetles this year!


Petunia's Gardener

Well, our slugs are a pest indeed, but no blisters at least! I'm looking forward to seeing the horseradish at work. I think I'm still in the bliss of a newer garden. The bugs haven't gotten too familiar with it yet.

Yolanda Elizabet

Apart from slugs I don't have much of a pest problem (so far) in my garden. I'm looking forward to see how you will combat those blister beetles (they sound nasty) in a eco friendly way. Lots of success!


I have slugs as well, but the only place they caused a problem was with my strawberries. I stopped them there by surrounding each plant with course sand. Slugs won't crawl over sand. I know that remedy isn't practical for an entire garden, but it works well for a small area!

Good luck combating your slugs, and thank you for the comments!

Gotta Garden

Yikes! I don't want them! Years ago, I read this book (it had a different cover...is that possible?...from my local library...anyway), but your brilliant post has reminded me that I need to read it again! Thanks!


I lost my whole batch of tomatoes to blister beetles 2 years ago. They nearly demolished all of my hostas that year too. I was so discouraged that I didn't plant last year. I am planning a large garden this year though and I am going to use that horseradish suggestion. I had read that they will leave eggs in the soil over winter so I am moving the garden to another area--even though it was 2 years ago, I don't want to chance it.


does anyone have suggestions for any organic solutions to keep them at bay that doesn't contain any type of sulfa or sulfates? I work at an outside resturant in south florida and we are over run with these pests and nothing we do helps. There are manatee and dolphins so it needs to be eco friendly. I can't find much information on these horrible pests that swarm at night! Please any advise will help us!

Kelly Walton

My mom suggested blending hot peppers and adding it to a spray bottle of water and treating the plants with that. She has not tried it herself, but she heard that it will ward off the bugs. I don't think it would kill them, just deter them.


Did this work? We have had the beetles the last 2 years-they ate all the loofa leaves one year, now our eggplant and tomatoes! Last year we drug a shop vacuum out to suck them up!

Marc and Renee

Yes Jane, this did work. I wrote this several years ago. That year I had no blister beetles on the plants next to the horseradish but still had them elsewhere in the garden in lesser numbers than the year before. The following year I planted the heirloom tomatoes as close to the horseradish has possible and only put hybrids in the farther away parts of the garden. That year I only had a very few beetles, almost none. The year after that and this year I saw no blister beetles at all. Now, I doubt that the horseradish is completely responsible for their disappearance, but I can tell you with certainty that they never attacked the plants right next to the horseradish, and it has flourished!

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