Blister beetles are sometimes found in mid-summer cuttings of alfalfa hay and can be toxic if consumed by livestock, especially horses. As few as 5 to 10 of these beetles can be fatal to horses when ingested because of the cantharidin in their hemolymph (insect blood).      Management to minimize blister beetle problems in alfalfa:

· Cut alfalfa at 10% or less bloom

· Manage weeds in and around fields, especially pastures

· Consider cropping practices adjacent to alfalfa. Blister beetles can be abundant in soybeans but are usually absent in corn.

· Do not grow solanaceous crops near alfalfa – both black and stripped blister beetles can be abundant in tomatoes and potatoes

· Sample field margins before cutting – blister beetles usually come from field margins and do not tend to move too far beyond the edges of alfalfa fields

· Monitor pastures for grasshoppers. Several blister beetle species develop in grasshopper egg pods. A high grasshopper population can produce high blister beetle numbers the following year.

Read more about blister beetles in the June issue of KY Pest News

~ Ric Bessin, from KY Pest News. Management steps from Lee Townsend.

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