These wasps not aggressive
Q. Here is a container of smelly debris. Insects have been coming out of it, but I cannot seem to catch anything. Please help!
Diane from Boardman
A. At first I thought it was simply a glob of dead grass, but as I began to examine it, I realized it was so much more. Taking the globs apart with a pair of tweezers was tedious work!
As I took the glob apart, I found six cocoons, and then I spied these little green katydid-like insects. One of the cocoons had the end opened and inside was a white wasplike pupa – the characteristic eyes and the “wasp” waist. I relayed the information to my colleague who was typing furiously on the computer, where she found the answer. These are Grass- Carrying Wasps and their pantry of Tree Crickets.
It seems these wasps (Isodonta mexicana) emerge in early summer, mate, and the females look for a suitable site to nest. Many times it is the lining of screens, between the screens and the frame. In the wild it is a crevice, a hole that bees have left, etc.
Solitary, the female carries collected grass and such to build her nest in the cavity. After this preparation she hunts for tree crickets (Oceanthus sp.), that she paralyzes and carries back to the nest. The eggs are laid and the emerging larvae will feast on the living crickets. In just four to six days later they spin a cocoon and pupate. Adults emerge 2-3 weeks later.
In our neighboring Pennsylvania, wasps produce two generations per year. There are several species in the United States.
These insect oddities are simply a nuisance, not aggressive but will sting if cornered, only a bit messy.
To learn more about them and identify them in your landscape (even around your home), go to: http://go.osu.edu/grasswasp
Answered by Stephanie Hughes, OSU Extension Master Gardener Volunteer and retired science teacher.