"Coccoons" found in dirt where wasps have frequented. #248935 - Ask Extension


"Coccoons" found in dirt where wasps have frequented. #248935

Asked June 01, 2015, 9:34 PM EDT

We have a brick planter box attached to the front of the house which has had many what look like wasps (thin bodies, orange legs, burrow into the dirt in the box as well as in the surrounding ground) for several years.  These creatures appear in late June through August, and don't attack unless I've disturbed their area (planting, watering).  I've just taken out some of the dirt (box is about 3 feet in depth), and have found many, many what look to be cocoons (these actually resemble dried dates).  Should I remove all of the soil, dispose of the 'cocoons', or just let it alone?  Is there any prevention to keep the 'wasps' away?  We've had a wasp nest in another part of the front yard, which I had the misfortune to discover by accident. 

Macomb County Michigan

Expert Response

Unfortunately, without pictures or a better description of both the insects and the cocoons, I can only give you some suggestions as to what they might be.  One possibility is that the insects are digger wasps.

This site shows many of the wasps we have here in Michigan. Do your wasps look like any of these?  http://insects.ummz.lsa.umich.edu/fauna/vespidae.html

As for the “cocoons”, they could be the pupae of sphinx moths or hornworms. Do the pupae “wiggle”?  What size and color are they? Do they look anything like the ones at this site: http://msue.anr.msu.edu/news/hornworm_caterpillars_the_big_cats_of_the_vineyard

Can you send me more information such as the size of the wasp-like insect, and color pattern on the abdomen, do they have white tips on their antennae, are they hairy or smooth? 

I assume you do not have pictures, but if you do, they would certainly help.

Before we would know how to control them, or if it would be necessary, depends on their identification. If the “wasps” are not aggressive, you might try to work around them.  Wasps are beneficial as they are good pollinators, and many capture insect pests for food.

If you could, please respond back to me with more information.  I am curious myself as to what these are.

Thanks for sending this to “Ask An Expert”.


Ruth Simon Replied June 02, 2015, 4:28 PM EDT

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