Normally, when an insect attacks the vegetable garden a gardener’s revenge is swift and decisive. Although we don’t mind sharing, some bugs take more than their portion, stripping plants to the point where we have to show them the door – or the neighbor’s garden – and order them to leave.
But this summer a beloved insect is back on the plants, nibbling on members of the carrot family and delighting everyone who sees them. Blaring their presence with a striping of black, white, and yellow, the parsleyworm (Papilio polyxenes) is one visitor you might want to let stick around.
When little, this caterpillar’s coloration has it dressed up like bird droppings, something that makes predators think twice before eating it. If the predator is determined to chomp them, the parsleyworm has another trick up its sleeve: they push a pair of orange, smelly “horns” from their head. As long as you’re not sniffing their head when they do this, it’s an endearing trick.
Yes, they’re eating the parsley. And the dill, fennel, and carrots. This is a small price to pay for nurturing the Black Swallowtail butterfly, which is what these very hungry caterpillars grow into. Should you want to control them, pick them from the plant or spray with Bacillus thuringiensis (Bt), an organic insecticide.
But if you choose to let these lovely creatures live to become adults, don’t worry if your caterpillars disappear from the plants. After stuffing themselves, the caterpillars roam about, looking for a place to spin their chrysalis in which to pupate. You’ll see your parsleyworm again, this time as an adult, a large black butterfly with yellow and blue spots.
Flitting through the garden, sipping nectar and visiting flowers, this butterfly and its two close relatives, Tiger Swallowtails, are as welcome as fireworks on the Fourth of July. Attracting them to your garden is simple: plant food for the caterpillars to eat, such as parsley, carrots, or dill for Black Swallowtails and willow, green ash, or chokecherry for Tiger Swallowtails. Don’t forget to add in flowers to give adults nectar to sip, particularly butterfly bush (Buddleia spp.), geraniums, butterfly weed (Asclepias spp.), or zinnia.
After all, you don’t mind sharing, do you?
This post was previously published in the Longmont Ledger.