BLISTER BEETLE ALERT

Livestock producers and especially horse owners need to be aware that blister beetles have been found in forage crops in central Wyoming.  Blister beetles larvae feed on grasshopper eggs and we certainly have an abundance of grasshoppers statewide this year, so we should be vigilant about the probability of finding this pest elsewhere as well.

Ingested blister beetles can cause severe illness and even death in horses.  Cattle and sheep can be affected, but illness is not usually as pronounced as it is in horses. 

Adult beetles inhabit and feed on blooming forage plants, especially alfalfa, and if consumed with green, cured, or baled hay will cause acute gastrointestinal and/or urinary tract symptoms.

The beetles secrete a toxin called Cantharidin which is very caustic if consumed.  Live or dead blister beetles in alfalfa or other hay are toxic, and even stored hay is a risk if contaminated with the beetles.  Hay containing blister beetles poses risks to livestock including blistering of the oral cavity, esophagus, and stomach.  Kidney and heart function can be impaired, and in severe cases can result in death.  Generally the first signs noticed include acute colic, diarrhea, and excessive salivation.  If blister beetle poisoning is suspected, veterinary care should be sought immediately.

In Wyoming, blister beetle infestation is more likely to occur in later summer months.  Therefore, first cutting hay is not as likely to be contaminated as hay cut later in the season.  Cutting hay before it blooms may decrease the likelihood of contamination.

Additional information on this topic can be obtained at the following website links: 

http://www.ext.colostate.edu/pubs/insect/05524.html#top

http://aces.nmsu.edu/pubs/_circulars/circ536.pdf

http://pubs.caes.uga.edu/caespubs/pubcd/C917/C917.htm

http://msuextension.org/publications/AgandNaturalResources/MT200209AG.pdf

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