Wooly Bear caterpillars with their broad bands of bristly black and brown hair are a familiar fall sight in much of the US. Children everywhere greet them with delight, and many teachers look upon them for lessons in lifecycles and metamorphoses. The very things that make them amenable to lessons in the classroom, can make them a gardener’s nightmare.
Wooly Bears are very adaptable to weather and seasonal changes. Depending on temperature and food availability they can produce 2 – 5 generations a year. Unlike many other caterpillars and garden pests, they can feed on a wide variety of vegetation. You may not see them most of the year, because they tend to hide. They feed and spin their cocoons at ground level, and the adults are short lived moths that fly at night. But when autumn is nearly upon us those wooly bears get restless, and wander about. The generation of wooly bears that we find in the autumn normally sleep through the winter in any cozy dry spot they can find. They wake in the spring, feed for a few weeks if they need to, and then spin their cocoons.
If you find a few of these fuzzy guys wandering around your yard, you might ask your child’s classroom teachers if they would like to raise them in class. Perhaps your kids might want to keep them as pets or as a science project. Hand raised wooly bears should have a container with loose sand or soil on the bottom and some pieces of bark to crawl on and hide under. They will be happy to eat clover, dandelion, and plantain leaves (and really, just about any leave you offer them). Prop the leaves up in their container so they are not laying flat. When the wooly bears quit eating, give them a layer of dry leaves to hid under and place their container in a cool dry, shady spot where you won’t forget them. Mist the leaves slightly once a week or so, to keep the wooly bears them from dehydrating. Check on them once in a while and if they are moving around offer them a clover, plantain, or dandelion leaf or two. If they eat it and stay active feed them more. If they don’t eat, put more dry leaves in their container and find a quieter, colder spot for them to rest. An unheated garage or shed is ideal, but the coolest quietest corner of the classroom or the driest spot in the play yard, may do in a pinch. In spring the wooly bears may wake up very hungry. Once they are nice and fat they will spin cocoons and within a few weeks the moths will emerge. They do not feed as adults, and only live long enough to mate and lay hundreds of eggs. If you have raised at least one male and one female they may start a new generation in captivity so the children can appreciate the whole cycle of their life.
I know the gardeners out there (and most of you reading this are gardeners) are saying, “Two to five generations a year, eat a wide variety of vegetation, lay hundreds of eggs, and she is suggesting we let a single one live?” Well, there are so many hungry creatures out there waiting to devour wooly bear moths, eggs, and immature caterpillars that it is a wonder any make it all the way to fall. And even those bristly fuzzy caterpillars are sought out by skunks, who roll them around on the ground until the bristles all fall off, and then they have lunch. (And you thought skunks were all bad?)
Now, I will be the first to admit that any wooly bears I find, when there are no handy kids to give them to, I promptly squish. I didn’t always do that, but after they mowed down my forget-me-nots, and then moved on to my artichokes, they are goners. I also depend on an army of hard working beneficial creatures to keep wooly bears, and other caterpillar populations in check. Those large yellow and black garden spiders that weave the perfect Halloween webs catch their fair share of moths. Lady bugs and lace wings, both adults and larva will happily eat insect eggs and young of many kinds. Wasps love caterpillars. And while a wasp is no match for a full grown wooly bear, they eat their fair share of the young hatchlings. And there are more hungry creatures in natures garden.
Huge Jerusalem crickets, those scary looking guys that are often called potato bugs or skeleton bugs are also fond of ground living caterpillars like wooly bears and cut worms. And then there are those giant science fiction California Glow worms, they look like giant millipedes and have glow in the dark spots and pulsating stripes. These natives are voracious predators of all ground dwelling pests, including our cute caterpillars and our slimy slugs. Raised beds, that provide good drainage, filled with a soil mix high in organic matter, and topped off with a coarse non-compacting mulch - are the best ways to insure these hungry creatures will make a home in your garden. And there are even more ravenous creatures waiting to serve your gardening needs.
The tiny braconid wasps, cotesia wasps, tachnid flies, and trichogama wasps all parasitize caterpillar eggs or larva, often killing their hosts quite dead. You can attract these little useful creatures for the cost of a few flower seeds and a little garden neglect. Braconid wasps like cosmos, sunflower, & marigold flowers. Cotesia wasps like mustard, carrot and sweet alyssum flowers. Tachnid flies like dill, parsley, and clover flowers. Last but not least Trichogama wasps are fond of wild carrot, dill, and golden rod. All of these little guys like aphid honey dew – them aphids are not all bad. For more information on Beneficial Insects see:
http://harvestsgardeningsecrets.blogspot.com/2006/05/beneficial-insects.html
So, here’s the basic caterpillar plan. Squish on sight, or give them to delighted children or classroom teachers. Ignore skunks and wasps to the best of your ability. Ignore small populations of aphids. Let the mustard and wild carrots grow and flower – even if the neighbors think they are weeds. Grow some of the flowers listed above and let them reseed. Welcome the tiny flying insects that are attracted and rest assured they are causing caterpillar nightmares. Keep adding organic matter to your soil and mulch with coarse plant material to attract ground dwelling predators. This is just a little bit of work and a whole lot of letting nature take its course. Some wooly bears will survive, but don’t forget, a few caterpillars (and aphids) munching a few leaves on your vegetables will stimulate the plants to make anti-oxidants and you will be the healthier for it!
Photo: http://www.whatsthatbug.com/caterpillar_2.html
Scroll down to: Isabella Tiger Moth, which is what the adult form is called.
More information on Garden pests:
Aphids
http://harvestsgardeningsecrets.blogspot.com/2006/08/aphids-are-among-us.html
Gophers
http://harvestsgardeningsecrets.blogspot.com/2006/03/gophers-and-gardeners.html
Stay tuned, next we will be planting the very yummy garden swedes and rutabagas. Meanwhile, you can probably find me out in the garden, Digging the Dirt.
Copyright 2006 Harvest McCampbell, from my column "Digging the Dirt," published in The Hoopa Valley People Newspaper, Sept. 19, 2006. Posted here with permission.
http://www.hoopa-nsn.gov/enterprises/newspaper.htm
