Sign up for the
Weekly Harvest Newsletter!

Published every Wednesday, the Weekly Harvest e-newsletter is a free Web digest of sustainable agriculture news, resources, events and funding opportunities gleaned from the Internet. See past issues of the Weekly Harvest.
Sign up here

Search This Site

Sign up for the Weekly Harvest Newsletter

What Is Sustainable Agriculture?

Master Publication List

Search Our Databases

Urban Agriculture

Energy Alternatives

Beginning Farmer

Field Crops

Horticultural Crops

Livestock & Pasture

Local Food Systems

Food Safety

Marketing, Business & Risk Management

Organic Farming

Pest Management

Soils & Compost

Water Management

Ecological Fisheries and Ocean Farming

Other Resources

Sign Up for The Dirt E-News

Home Page

Contribute to NCAT


Newsletter sign up button

· Privacy Policy · Newsletter Archives

RSS Icon XML Feeds

RSS 2.0: Events, Breaking News, Funding Opportunities Atom: Events, Breaking News, Funding Opportunities


NCAT strives to make our information available to everyone who needs it. If you are a limited-access or low-income farmer and find that one of our publications is just not in your budget, please call 800-346-9140.


How are we doing?


Find Us on Facebook Follow Us on Twitter Follow us on Pinterst Visit the ATTRA Youtube Channel
Home  > Question of the Week

Question of the Week

Permalink What are the best organic methods for dealing with a blister beetle infestation?

Answer: For many market farmers, blister beetles can wreak havoc on crops in a very short time. The beetles seem to prefer tomatoes, potatoes, and chard, but easily move on to peppers and eggplants. More importantly, they infest hay and are poisonous to animals feeding on the hay, even if the beetles are no longer alive, due to the presence of a toxic chemical in their bodies called cantharidin. Handling the adults should be avoided, as cantharidin can irritate or blister skin on contact. If handled gently, this may not be a problem.

Populations tend to appear suddenly in June and July and usually will feed together in groups. Blister beetles usually overwinter as last-stage larvae and prey on either grasshopper eggs or bee eggs, so keeping grasshopper populations low is necessary to effectively reduce blister beetle populations. If grasshopper populations are high one year, there is increased likelihood that the following year will see higher than normal blister beetle populations.

Some effective options to control the adults are pyrethrum, a broad-spectrum botanical insecticide, and a kaolin clay product sold under the brand-name Surround. Surround is not directly toxic to the beetles but acts in two ways: it changes the color of the plant, thereby confusing the insect, and it also causes most insects that land on a kaolin clay-coated plant to spend much time grooming themselves to remove the clay particles. This reduces the time they spend feeding. Keep in mind that many plants can withstand considerable defoliation before there is a decrease in yield. Neem-based products (containing Azadirachtin) have also reportedly been effective against blister beetles, though if you have a large infestation of blister beetles, you might consider using a formulation of spinosad.

Other management strategies include early planting and harvest of crops to avoid the June/July peak blister beetle season. Row covers are also an option, but you must be sure that no beetles will emerge beneath (inside) the row covers. If your plot is relatively small, then the beetles, which tend to congregate in one area, can be knocked into a bucket of soapy water, which will kill them. Using a preferred crop or even a preferred wild host like passion vine as a trap crop is also an option; the trap crop can then be treated for the beetles. Lastly, creating environments attractive to blister beetle predators, including robber flies and birds such as meadowlark, bluebird, and scissor-tailed flycatcher, can help reduce the population.

See for ATTRA’s ecological pest management database and sourcing information for the above-mentioned biorationals.

For more information, see the following ATTRA publications:

Biointensive Integrated Pest Management

Farmscaping to Enhance Biological Control

Grasshopper Management

The mention of specific brand names does not constitute an endorsement by ATTRA, NCAT, or USDA.



« What could be causing the heads of my young white cauliflower to turn yellowish-brown? :: The farm I just purchased previously struggled with foot rot within their sheep flock. How long will it take the foot rot organism to leave the ground? »


No Comments for this post yet...

Question of the Week Archives