Mysterious Holes in my Lawn!

This spring the Insect Diagnostic lab has received several phone calls regarding homeowners who are finding numerous small holes in their yards, sometimes accompanied by dying grass. The following is an example shared with me from a golf course in Hutchinson, KS. The complaint was that the Bermudagrass was dying and that there were numerous holes in the same area, which were thought to be related.

Upon closer investigation, it was determined that the dead spots in the grass were the result of a disease called spring dead spot (SDS). So what was the cause of the mounds and holes? In most cases, it is not possible to simply peak down the hole and see what is there. So, a “flushing solution” was placed in one of the holes to force the inhabitant out (see recipe below). Soon, a wet, soapy camel cricket emerged. It appears that the camel crickets, not typically associated with turf had simply moved in and exploited the “easy digging” bare spots created by SDS.

The moral of the story is that, while the answer may not always be simple or straight forward, a little investigation may explain a lot. Here are some arthropod (and other) culprits to consider.

:   If the soil in the yard has a significant population of earthworms, there may be piles of small, granular pellets of soil. If these piles are pushed aside, there is other no hole in the top. This is most common in spring and fall when soil is moist and earthworms are active. Ground bees and Cicada killers   There are several species of ground bees that will create cylindrical tunnels in lawns, creating egg chambers. The holes are typically about « inch wide. Cicada killers may produce a hole that is up to 1 inch in diameter. Both of these insects may leave mounds of dirt near the entrance of holes and prefer looser, sandy soil with sparse vegetation.

These are only found in areas with consistently wet soil. They create 2-4 inch high piles of mud balls surrounding 1 inch wide holes.

Emerging insects: Many insects, such as June beetles and cicadas, overwinter in the soil in immature life stages. As temperatures begin to warm, they will complete development and emerge as adults. They may leave holes in lawns of various sizes and may be accompanied by small mounds of dirt pushed off to one side.

So how do you determine what is in the holes? Bob Bauernfeind, Extension Specialist, recommends a flushing solution. Mix 1 Tablespoon of Lemon Joy into 1 gallon of water and pour it down one or several “mystery holes” and watch to see what comes up. When the holes are created by emerging insects, there will be no insects, but it is possible that a cast skin may float up to give some clue to what was there. It is important to stress that large sections of dying or yellow yard may be the result of a disease rather than the resident of the holes in your yard.



Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: