How to Control Blister Beetles
If you have wild lupines growing on your property, you have probably noticed blister beetles feeding on the plants. These beetles grow to a length of 2 inches or more, but are commonly about an inch long. The most common blister beetle in my area is a dusky blue-gray color, but they can be jet black or striped.
According to the University of Florida, blister beetles belong to the Meloidae family and encompass over 2500 species. These beetles can be found on lupines in the early spring, but may also infest your garden and devour foliage. While they are considered beneficial because they also feed on grasshopper eggs, when they attack your flowers and vegetables you may not see their value. Getting rid of them can be a bit of challenge.
Try these methods for controlling blister beetles:
- Hand Picking: While this is an effective method, you must wear protective gloves. Blister beetles get their name from their ability to blister the skin if you pick them up. They emit a substance called cantharidin that irritates and blisters skin and mucus membranes. If you choose to handpick blister beetles, don you gardening gloves. Many hold a bucket of soapy water under the foliage of the plant and give it a little shake to drop the beetles into the water. Old-timers used a branch of pine to sweep them from the plants and into the waiting mixture of soap and water.
- Organic Pesticides: If you aren’t up to the task of hand picking these crawly creatures, try applying an organic pesticide to control blister beetles. Look for one that contains spinosad, an organic pesticide made from fermenting naturally-occurring bacteria from the soil.
- Chemical Pesticides: If you aren’t opposed to using chemical pesticides or are having difficulty controlling blister beetles with less aggressive methods, use a pesticide that contains either carbaryl or lambda-cyhalothrin.