Avant Gardener: Cabbage worms will destroy plants unless controlled
By Kyle Valentini
July 10, 2011
260
Summary: Cabbage is easy to grow if you can keep the pests at bay. Cabbage worms are the larva of the Cabbage White Butterfly and they can do a lot of damage rather quickly. You can avoid toxic sprays and powders and still get rid of cabbage worms. Preventing the butterflies from laying their eggs in the first place is the key to success.
The mini gardener became fond of cabbage when she started seeing the itty bitty organic ones available at the grocery store. Grown in California, these young, tender varieties are delicious cooked or raw and are relatively affordable as far as an organic product travelling three thousand miles in a refrigerated truck is concerned.
In the spring when we first began planting she had asked if she could plant a few cabbages. I tend to stay away from brassicas because they inevitably end up being destroyed by the velvety, green, one inch long worms that are the larva of the Cabbage White Butterfly and I know wonderful local farmers that grow them in a multitude of varieties.
I like a low maintenance garden. Cabbage worms can do a boat load of damage in a few days. They are not low maintenance. They eat the cabbage leaves in order to build up enough energy to build a chrysalis so they can become a beautiful, white butterfly that will lay eggs on next years cabbage. Can you blame them? Cabbage is good and a cozy chrysalis sounds like a delightful way to spend the winter.
Hand-picking the worms and eggs off is an effective means of control but if you have a lot of cabbage youll find this to be tedious work. They are very difficult to see due to their color conveniently being exactly the same as green cabbage leaves. When it is said the Lord works in mysterious ways this couldnt be because he is entertained watching us make fools of ourselves battling a one inch long worm with its own agenda, could it?
Cabbage White Butterfly eggs are yellow and should not be mistaken for the dark greenish black things that are actually the cabbage worms, uh, droppings.
Keeping a row cover over your cabbage from day one is a way to prevent the butterflies from ever laying their eggs to begin with. I did not do this. I waited until the plants were well established and beginning to form heads. I had faith. I am currently hand-picking cabbage moths off the plants while I mutter things under my breath like, why didnt I put row covers on the plants earlier and some gardener you are.
In early spring you might notice the dainty creatures fluttering about and you might be tempted to say, Oh, look at the pretty butterfly! Dont. With its pretty white wings and those adorable little brown spots, know that she is the enemy. Do not be fooled by her coquettish ways. She will innocently suck the nectar from the myriad of spring flowers you planted and then begin her egg laying without batting her antennae.
Bacillus thuringiensis is a microorganism that produces chemicals that are toxic to cabbage worms. It occurs naturally and has been found by people that actually look for weird microorganisms for a living. It is also made in a lab and is conveniently located on a shelf at your local nursery. If hand-picking is not an option, you can try Bacillus thuringiensis. Make sure you write it down, however because your well-versed local nursery employee might misunderstand what you are saying and hand you a tub of yogurt instead. Yogurt, as you might imagine, is not toxic to cabbage worms.
When cabbage worms ingest Bacillus thuringiensis it essentially shuts down their digestive systems. They stop feeding and die of starvation within a few days. Bacillus thuringiensis needs to be reapplied often as it does not stay potent for very long.
I choose not to use Bacillus thuringiensis because like most things created in a lab, it has been abused by the agricultural industry. Using genes from Bacillus thuringiensis, crops like potatoes and cotton have been developed so they will contain the proteins that kill the pests that feed on them. These genetically engineered crops no longer are effective at controlling the pests according to the very company that created them.
I choose to let God work in mysterious ways and laugh just a little bit as I hand pick the velvety green worms off my cabbage plants.
If your cabbage plants have sustained some damage there is no reason to throw in the trowel. As long as enough leaves remain to allow photosynthesis to occur you should be able to harvest healthy cabbage.
