Walnut Caterpillar

Walnut Caterpillars on the Prowl

Walnut caterpillars (Datana integerrima) are native insects meaning that year-to-year population densities are usually kept in check by predators, parasitoids, and pathogens (the 3-Ps).  However, we occasionally see "outbreak years" when caterpillar numbers surge ahead of the combined natural suppression provided by the 3-Ps.  I'm not suggesting we are experiencing an outbreak season, but walnut caterpillars are certainly not hard to find!  In fact, I've come across the characteristic patchy defoliation produced by colonies of these caterpillars on their namesake host in two...

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Joe Boggs