August is the peak month for harvesting garden vegetables. It is also peak cabbage harvesting month.
Cabbage butterflies are the number 1 enemy of plants in the cabbage family which includes cauliflower, broccoli, Brussels sprout, kale (both edible and ornamental) and—of course—cabbage.
The bright-white butterflies (seen on the rleft) lay eggs on susceptible plants and—very shortly thereafter—voracious larvae (cabbageworm) emerge and chew large holes in the foliage.
I’ve battled cabbage butterflies for years and they are the category of insects that I find the most irritating. When I finally get my broccoli to the point where it can be harvested and eaten, I have zero tolerance for worms concealed in the crowns. Green worms and cheese sauce are a very disgusting combination!
The solution to cabbage worm control is a weekly application of a product called BTK (Bacillus thuringiensis var. kurstaki). BTK is a bacteria that specifically targets cabbageworms and their relatives and is very safe to apply. It is best to apply BTK in the early morning or evening because the bacteria don’t like hot, dry weather during application.
Alternatively, you can use crop cover to prevent cabbage butterflies from laying their eggs altogether.
Water and sun-penetrable, crop cover is an effective and organic way to prevent pests such as cabbage worm from damaging your crop.