Spring Cankerworm – Identification
Spring occasionally brings an influx of creatures you hadn’t noticed before.
A warm winter can result in thousands of little green caterpillars raining down from oak trees on silk strands. Stnding under an infested tree is distasteful as tiny black waste pellets sprinkle you from above.
Welcome to the periodic appearance of spring cankerworm (green inchworm). The caterpillars mostly feed in trees but I’ve heard reports of damage to roses too. Whatever their origin, they drop down from it on a silk thread before pupating in the soil.
There is not much to be done when they are in a tree. You could spray the organic Bacillus thuringiensis (B.t., Dipel, Caterpillar Attack, etc) but getting it high enough to be effective would be difficult.
The great news is that their lives are short; they will be gone a couple of weeks after first being noticed.
And here is a recipe for even more organic control