Exochus

Before you swat that tiny wasp away, take a closer look.


​It may be one of the Good Guys.

Adult Exochus sp. (UCANR)

Some wasps, such as Exochus, work to protect your apple, grape, plum, and citrus crops against leafroller caterpillars.


Exochus is a group of beneficial parasitic wasps in the ichneumon genus. There are over 270 species of Exochus. Most Exochus are small, narrow-bodied wasps with long antennae and sturdy legs. Some Exochus species have wide, bulging, triangular faces, but not all.

Female Exochus wasp (Tapani.Hopkins)

Exochus prosopius (James Lindsey)

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Like other ichneumon wasps, Exochus females insert their eggs into the larval stage of many leaf rolling caterpillars, such as the orange tortrix and the obliquebanded leafroller. The eggs then hatch inside the caterpillar and begin feeding. You can see video of an Exochus female attacking a caterpillar here. The video is bit long, but fascinating.


​These tiny wasps serve us well in the garden, so avoid using any broad spectrum pesticides and let nature take its course.