Wednesday, December 15, 2010


A Small Cabbageworm on the Underside of a Cabbage Leaf

Cabbageworms are soft, velvety green caterpillars - they're the larvae of a white moth that mates from December through February. They attack cabbages and leafy greens, including radish and horseradish tops. They're very destructive and it doesn't take them long to destroy a winter garden. In past years, the leafy greens they didn't eat were arugula, broccoli rabe (rapini), endive, escarole, radicchio and some of the mustard greens.

Summerweight Row Cover & Tulle Nets
(It looks sort of like a garden wedding scene)

I highly recommend covering arugula, broccoli, cabbage, chard, kale, lettuce, salad greens and spinach with tulle or light row covers by mid-November and keeping them covered until the end of February. The caterpillars are very hard to find when they're small. Some of the greens will continue to grow and outgrow the damaged leaves. If the moths lay their eggs on the cabbage leaves after the cabbage heads have formed, the larvae will tunnel holes throughout the cabbages and ruin them.

Following is a link for more information and product recommendations for cabbageworms.

Spinosad is one of the recommended organic gardening products for cabbageworms but spraying a garden regularly is both expensive and time consuming. Row covers and tulle nets have worked very well for me for damage control. Last year the worms were noticeable in December but this year the damage began just before Thanksgiving.

The late fall and winter daytime temps are usually in the low 80's and I was hesitant to use row covers. I thought the cabbages would perish undercover but they don't appear to have any heat stress.

Wal-Mart is a good place to buy tulle and light row covers can be purchased online at Gardener's Supply Company and Johnny's Selected Seeds. Row covers need a simple frame. This can be created with bendable pieces of PVC slid over stakes or cut pieces of rebar that are pushed into the ground. Hoops are also sold at these online garden suppliers and a bendable heavier gauge wire will work also.

A Veiled Broccoli Plant 

The row covers are wide enough to use with container gardens - they're just wide enough to cover the container grown cabbages. For broccoli and other tall plants I make a tulle net - it looks like a mini version of a mosquito net. I tie it at the top to a 4 foot stake and secure it around the container or the base of the plant. If you have the time and skills, framed covers made of more durable materials could be constructed as well.

A cool idea to use as a cover!

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