Fuzzy yellow Caterpillars

(Question)

Hi there
My name is Jessica. I am a recreation therapist at Humber river hospital on the adult mental health unit. As part of our program we have a rooftop courtyard garden in raised planters. The patients grow the plants and then use them in our cooking group.
This year we have about a million little yellow fuzzy caterpillars who are eating all of our plants. They started with the mint and basil, and moved onto zucchini fruit when I sprayed dish soap and water on the damaged plants. Our honeysuckle is absolutely covered in holes.
We don’t get a lot of birds up there so the darn things just are not being eaten. They are everywhere! What should we do to get rid of the darn things? I fear our peppers and tomatoes are next.
Thanks!

(Answer)

This is likely one of our most common visitors.  Spilosoma virginica is a species of moth in the Arctiinae subfamily. As a caterpillar, it is known as the Yellow woolly bear or Yellow bear caterpillar. As an adult, it is known as the Virginia tiger moth.

Hand-picking this caterpillar and putting it into a pail of soapy water is a method that many gardeners use.  Do wear protective gloves – although these caterpillars are not poisonous in any way, their bristles may cause irritation to people with sensitive skin.   Here is a website with a good photo that can help you to make a positive identification:  https://owlcation.com/stem/furry-caterpillar

Incidentally, the City of Toronto has a good guideline for biodiverse green roofs which includes a section on attracting birds to your rooftop garden: https://web.toronto.ca/wp-content/uploads/2017/08/8d24-City-of-Toronto-Guidelines-for-Biodiverse-Green-Roofs.pdf

Very best of luck – it is a wonderful project you have there!