I have read (and tried) that dusting with with wood ashes will keep away flea beetles and found that the results were limited and needed to be continually replaced. I suspect this will work the same but I will try it out next season. BT works really well for killing the cabbage worms and seems to allow the wasps to live and work at the job too though I expect it sends them elsewhere to look for a meal.

I wonder what flowers would make good companion plants to attract the wasps that eat the worms? That would probably make a good line of defense.

I wonder what flowers would make good companion plants to attract the wasps that eat the worms? That would probably make a good line of defense.

If I was going to try it, which I wouldn't, I'd sure make sure it contained minimal flour or once it rains you will will have a gooey, gummy, pasty mess all over the plants.

Dave

Good point on the flour

I think dusting with diatomaceous earth would probably be better at this point.

I still wonder about companion planting to prevent cabbage worms though. What would a good choice be? Chives maybe?

Since companion planting and its claims is merely a school of thought it has its own forum so you may find advice on that over on the Companion Planting forum here rater then this forum.

But do keep in mind that despite some of its claims, companion planting does not prevent anything. At best it is geared toward somewhat discouraging some pests.

While there are many ways to treat for cabbage worms and cabbage loopers, there is only one way to prevent them. That is by blocking the moths that lay the eggs access to the plants with row covers.

Dave

The moths will avoid tomato leaves. Wasps will come to fresh fruit--rinds, etc.

I've read that umbrella-type flowering plants such as Dill, carrots, parsley, and alyssum attract predatory wasps.

Kevin

Row covers. Row covers. Row covers. Effective, reusable, safe, easy.

Don't knock the flour until you have tried it. Around here, folks use a light sprinkle of flour to protect cabbage and broccoli from worms. Apparently they eat it and swell up or something. Anyway, its been used for decades, is safe, easy and inexpensive. Why not try it?

Yes, while companion planting's effects on soil or plant growth are not scientifically supported, certain plants are sure to attract beneficial wasps and flies to your garden and it is hoped feed on the caterpillars (and other pests!). In addition to those Kevin mentioned, I'd add cilantro and fennel. Fennel can be invasive, so make sure you have an appropriate place to plant it. (ps cilantro and parsley overwinter in my zone 7 garden)
I have struggled to grow any Brassica crop until this year, when I kept the plants covered with row cover attached to hoops. Occasionally cabbage moths do get in, plus slugs can be an issue for me, so I also use diatomaceous earth. With those two strategies you can save the flour for baking!

we use flour lightly sprinkled on our broccoli and cauliflower as well as our potato plants....gets rid of the worms and beetles and does not turn gooey or gummy.

I tried most of home made stuff. Unfortunately it does not work.

To expand on what Dave said, I would say nothing prevents anything. Companion planting is part of good strategy, along with mineralizing the soil.

I've noticed white moths in the garden around my brussel sprouts. And something has been eating holes in my greens and bean leaves (could be a moth) I've heard basil is a good companion plant in the garden, marigolds, mint (but mint will take over the garden so it's best to plant in a container and place it in the garden. Here's a good article. http://www.mnn.com/your-home/organic-farming-gardening/stories/12-plants-that-repel-unwanted-insects