Beautiful Butterflies Come From Very Hungry Caterpillars

Recently I've seen white butterflies flitting about the garden.  While lovely to look at, they signify bad things to come in the garden.  As they flit about they are depositing eggs on the undersides of the brassica plants.  They are the adult form of the imported cabbageworm.

 

The eggs hatch in five to seven days. The larva (cabbage worm) feeds on plants of the cabbage family, building up energy to make its chrysalis and metamorphize over the winter.



Because of their voracious appetite, an "infestation" can be as few as two or three worms per plant!  Their presence is unmistakable. The worms chew big holes in the leaves of their host plant.  My cabbage and brussel sprouts are being most effected, but they enjoy the broccoli, too.  The cabbage worms usually hang out on the undersides of leaves and produce dark green droppings that are fairly noticeable.

A serious infestation can result in the death of the plant, since increased leaf destruction means decreased photosynthesis.  A minor infestation can make plants look ugly, but they're still edible. Just wash them carefully and inspect cabbage and broccoli for any worms that have made their way to the interior of the heads.  A good salt water soak should bring out any hidden worms.  So what to do in the garden?

To prevent infestation in the first place, plants may be protected with floating row covers, especially in spring and early summer, when egg-laying activity is at its highest. I obviously missed my opportunity to do this.

Check plants frequently for worms, especially if the butterflies have been seen nearby.  Hand-pick and destroy any worms found.  That's been my line of defense.  My  method of destruction?  Smoosh them between my fingers!  Bug guts are nothing when it comes to protecting my garden.  Here's an interesting tip:  To prevent the worms from burrowing into cabbage heads, insert each head into a nylon stocking, and leave it on until you harvest the head.  I haven't tried that yet, but I may!

If there's a serious infestation, purchase bacillus thuringiensis (BT) from the garden center and apply it according to the directions.  This is an organic treatment.  Vegetables may be picked and consumed anytime after spraying, and pets and family may return to the treated area immediately after spray deposits are dry.  Caterpillars must eat a small amount of treated leaf to get a lethal dose. Caterpillars stop feeding within a few hours after taking a bite of the treated leaf and death follows within a few days.  See http://organicgardening.about.com/od/pestcontrol/p/cabbageworms.htm for more information about BT.