Blister Beetle

Gardener's friend or foe? The answer depends on this insect's life stage.
Related To:
ISP-9612514_Blister-Beetle_s4x3

ISP-9612514_Blister-Beetle_s4x3

Named for the effect it has on human skin, the blister beetle is both a gardening pest as well as a friend, depending on its stage. As a larva, it feeds on grasshopper eggs but as an adult, it feeds on alfalfa and a variety of vegetable crops, depending on the species. More than 300 species of blister beetles are found in the U.S. — many (but not all) have long and narrow bodies; in nearly all, however, the head is larger than the body segment next to it. Color ranges from solid black or gray to striped or metallic.

Blister beetles contain a toxic substance, cantharadin, that can cause blisters to form on the skin. The toxin is especially problematic for livestock that eat feed contaminated by the beetles. Horses are especiallly susceptible; horses that eat sufficient quantities of the feed can become extremely ill and die. Blister beetles vary in the amount of cantharadin they contain. It's been estimated that 80 three-striped blister beetles or 1,100 black blister beetles would provide a lethal dose of cantharadin for a 550-lb. horse.

Applying an insecticide is usually not an effective control for the blister beetle. Hay growers typically use mechanical means for getting rid of the pest. If you find blister beetles in your veggie garden, pick them off by hand — and be sure to wear gloves!

Next Up

Stag Beetle

Not considered a pest, this beetle lives on decaying wood in tree stumps and fallen logs.

Ground Beetle

This fast-running beetle is a friend to gardeners.

Gardening Q & A: Summer Snowflake Plant and More

Master gardener Paul James talks about pruning candles, cool plants, and no-hassle manure tea.

How to Garden in Just 15 Minutes a Day

No time to garden? Learn 10 easy tricks to multiply minutes in the garden.

Tropical, Hardy Hibiscus

Rose of Sharon, a hardy hibiscus, is quite similar to tropical ones and can be grown in many more areas.

Saddleback Caterpillar

The spines on this colorful caterpillar deliver a potent sting.

Glossary of Gardening Terms

Whether you're just starting out or need a refresher, brush up on essential gardening terms with this easy glossary.

What Is a Gall?

Get the facts on galls and why they form on plants.

When to Use Pesticides and Fungicides

Chemicals aren't always needed. Learn when -- and when not -- to use pesticides and fungicides in your garden.

Spiny Elm Caterpillar

The spiny elm caterpillar is the larval stage of the mourning cloak butterfly.

On TV

Island Life

6:30am | 5:30c

Island Life

7am | 6c

Island Life

7:30am | 6:30c

Home Town

8am | 7c

Home Town

9am | 8c

Home Town

10am | 9c

Home Town

11am | 10c
On Tonight
On Tonight

Love It or List It

8pm | 7c

Hidden Potential

9:30pm | 8:30c

House Hunters

10pm | 9c
11pm | 10c

House Hunters

11:30pm | 10:30c

Hidden Potential

12:30am | 11:30c

House Hunters

1am | 12c
2am | 1c

House Hunters

2:30am | 1:30c

Follow Us Everywhere

Join the party! Don't miss HGTV in your favorite social media feeds.