Darkling/Mealworm Beetles In Hay Or Feed DR. LEE TOWNSEND Adults often wander some distance from their LEXINGTON, KY. breeding site and enter stacked hay so it can be une 19, 2012 –Finding beetles in stored al - hard to find the source of the infestation. falfa hay or animal feed raises an immediate Sanitation is the key to dealing with darkling red flag. Are they blister beetles? If not, what beetles but it can be difficult to find and elimi - aJre they and are they harmful? Usually, it is nate all breeding sites of these insects. Fortu - darkling beetles, they larvae are called meal - nately, their development is relatively slow so it worms. These insects tend to hide so they can takes time for large numbers to develop. Brooms be found under, in, or between stacked hay and shop vacs need to be used to clean all ac - bales. Darkling beetles do not contain can - cessible fines. tharidin, the toxin in blister beetles, they are not Infestations in stored bulk feed are more diffi - harmful. cult to address, depending on the amount that is Darkling beetles are different from blister bee - present, how quickly it will be used, and time of tles. The most obvious feature is the distinctly year. It may be best to feed out the supply and narrow “neck” of a blister beetle which lies be - thoroughly clean the storage area and sur - tween the head and thorax of the insect. In con - roundings before re-filling it. A pyrethrin spray trast, the “neck” area of the darkling beetle is labeled for use in feed storage areas after clean wider than its head. Also, they have hard front up will help to eliminate surviving insects. In - wings compared to the soft, more flexible front formation on blister beetles in alfalfa is available wings of blister beetles. in this factsheet - www.ca.uky.edu/entomol - Mealworms, the larval stage of the darkling ogy/entfacts/ef102.asp . ∆ beetle, are common in stored or spilled grain or DR. LEE TOWNSEND: Entomologist, University feed, where they eat broken kernels and fines. of Kentucky