In general, I’m a lover of all life forms but as a farmer, certain insects can send me over the edge. One particular white butterfly, that shows up first thing in the spring and has been seen in my garden all the way into December, has me reaching for a tennis racket more often than not.
The Imported Cabbageworm Butterfly is a European native that lays eggs on the entire Brassica family, from kale to cabbage and kohlrabi to Brussels sprouts. The butterfly lays tiny white eggs on the leaves of this vegetable family and when the little larvae hatch, they immediately begin to eat holes in the leaves. I’ve had entire kale plants turn to sticks with only the mid-ribs left.
Because the Brassica family is so large, the impact of this one little pest can be quite devastating. So what is a grower to do? One tactic is to go out to your plants on a regular basis and inspect the leaves, rubbing off the little eggs that are about the size of a grain of salt. This task is easy to do if you’ve only got a few plants.
Hand-picking the caterpillars is another option. Unfortunately, they’re extremely well camouflaged. They turn the exact-same green colour as the leaves so finding them is not as easy as it sounds.
There is an organic spray option using a bacerterium. BTK, or Bacillus thuringiensis kurstaki, is a soil-borne bacterium that infects the stomachs of caterpillars and causes them to die. The spray has no impact on bees or other insect families and breaks down in sunlight so is considered quite safe.
If I’ve planned properly, however, I try to prevent the problem in the first place by using a spun polyester cloth draped over my young plants. Floating row cover, also known as Reemay or Agri-fabric, is a light-weight cloth that allows sunlight and rain to pass through but prevents insects from laying their eggs on or near your plants. I’ll be draping my young seedlings, while they’re still in their trays. The fabric will then go out into the field to protect the plants at least until the weather turns in the late fall.
So, if you’ve been avoiding planting kales or cabbages for the fall because of this pest, here are a few techniques to help you keep your sanity!
PS. Here’s what I’ve been seeding this week: Radicchio, endive, more kale, green onions.
Cabbageworm butterfly eggs
Arzeena Hamir is a Professional Agrologist and owner of Amara Farm in Courtenay. Along with Ripple Farm, she runs a 40 share CSA called Merville Organics. In her spare time, she sits on the Boards of World Community, Fertile Ground,and the Comox Valley Growers and Seed Savers.
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