These wasps have been flying low over the
garden for a couple of weeks now, but I only got a closer look on
Sunday morning. Five had settled down on a young apple tree, and
the cool, dewy morning kept them in place even when I stuck the camera
in their faces.
I'd assumed the insects were adult squash vine borers, but I wasn't
even in the right ballpark; instead of being garden pests, these wasps
are our new best friends. Digger Wasps (Scolia dubia) are the primary
natural enemy of both Japanese
Beetles and June Bugs. The female wasps burrow into the soil
in search of beetle grubs, paralyze the immature beetles with their
stingers, then lay an egg on each paralyzed grub. The grub serves
as a comatose but living buffet for the baby wasp, who eats the grub
beyond repair. Now I just need to figure out how to further
encourage our Digger Wasp population and knock out the Japanese Beetles
once and for all!