Tuesday, October 16, 2012

Fuzzy Orange Caterpiller

Cleaning up the garden can turn up some great (and not-so-great) surprises. One that might at first be alarming is the discovery of a fuzzy orange caterpillar.

Spilosoma virginica; Photo by Amy Whitney
Anyone who has lost a tomato plant to hornworms or to armyworms is likely to scrutinize every caterpiller fairly closely.

This particular caterpillar, though, turns out not to sting (like some other fuzzy caterpillars) and not to be a significant garden pest. It is a fairly dark specimen of Yellow Woollybear.

According to the book Garden Insects of North America by Whitney Cranshaw, many of these are more yellow, some so pale as to almost be white, but some are actually brown.

The adults are a white moth, the Virginian Tiger Moth. Cranshaw includes this information about the Fuzzy Woolleybear:

"Larvae chew foliage. Damage is rare and most commonly occurs late in the season when many hosts die, causing the yellow woolleybear to concentrate on remaining succulent crops."
The caterpillar pictured above was found in a sweet potato patch, which was being harvested at the time, so Cranshaw's information is especially apt. The caterpillar was found both when and where it would be predicted to be found.

As with all caterpillars, even though this one doesn't have any painful-to-human defenses, it is very easy to damage the larva by picking it up or trying to move it by hand. Any damage might not be immediately visible, but, to avoid harming them, caterpillars should not be handled at all.