hay mites

Asked September 24, 2019, 1:35 PM EDT

I work for a private farm in Oxford Michigan. Everyone who is employed and have come in contact with the hay, have bites on chest, back, abdomen , arms and groin. I would like to know what type of bug is causing the problem.

thank you

Oakland County Michigan

3 Responses

Itch mites (Pyemotes ventricosus) can produce the symptoms you mentioned in your comments. Without a positive identification of the insect causing the bites, it's difficult to say what may be the cause.

You are the third call in the last two days discussing bites as a result of baling hay in the last few week.

Itch mites are predatory and will feed on what they can on the inside/outside of a bale for as long as there is food available. After their food supply is depleted, they will die. This can last into the winter time.

So, if you want to positively identify what the problem is, a sample for identification needs to be sent to MSU Plant and Pest Diagnostic Lab. The website for the lab and submittal forms is located at the following address?


I tried to look at a sample of hay with just a magnifying glass. No luck.

Do i I just send a sample of hay?

No don't send the hay. What you can do is take some packing tape and pat a few bales where you know the problem exists. Look at them with any magnifying glass to see if they are actually on the tape and if they are, then send the tape to the lab.

The BEST option is to contact Howard Russell directly and ask him how to submit a sample. His direct phone number is 517-353-9386.