have you tried netting or shade cloth?

I use bt (Dipel) with good results.

I'm using bt this coming year. Like you, I tried various sprays to no avail, they are a huge problem here and I couldn't keep up. I don't think netting is an option for me personally due to the high winds we get in this area. Sometimes it is a miracle to have a plant even standing after a day of wind gusts, much less trying to fight with netting. Lori

BT works wonders.

Kevin

the netting has to be secured to a frame.

Yes, I realize that. Lori

I'm certainly equal to the task of installing netting cleanly and securely... my garden is practically Fort Knox with fence/wire protection on floor, walls, and roof! However, I question whether a screen or net will keep caterpillars (worms?) out? I have to admit I don't know how the particular critters that like my cole crops enter the garden area... do they burrow from the soil? Crawl overland? Have the eggs been planted already, waiting to issue forth the horde of tiny beasts? I like the simplicity of the Bt solution... but I'm always tempted by a good project as well. I would need to know that it had a good chance of success before I took the time, however.

Creativeguy, those pretty little white "butterflies" that flit over your garden are the proud parents of most of those catipillars (sp?). There are a few different kinds but those are what I see the most here. Netting is a great way to keep them off the plants so they don't lay their eggs but it just isn't feasible for me. Lori

So, to be clear, if I can keep the moths out of the area where I've planted the crops in question, I should be able to control the caterpillar population? The eggs won't be laid until the plants are there to support them? I suspect I'm straying dangerously close to needing to switch forums, (to pests and diseases) but last season when I was regularly spraying with the organic pesticide the reason the bugs kept coming back was because new eggs were regularly being laid? I appreciate the responses so far!

I had cabbage worms decimate my brassica the first year I tried to grow them. I have been using BT ever since. You only need to spray 3-4 times (or less) the whole season, and it doesnt harm the beneficial insects. It can and will kill butterfly larvae though, so if you are sensitive to that...........I have so many colorful flowers in my garden that I am hoping the butterflies have better places to me than my Brassicas.

creativeguy:

Sure you could do that, but are you going to do the same in the summer and they lay eggs on your summer crops and then the grubs burrow in the soil. I'm not sure if this is how the life cycle of a cabbage looper works, but the spring through fall is when I see them flying around. Yet, my brassicas in winter seem to always have some sort of damage. That's why BT is a no brainer. I spray it on all my peppers and maters in the summer for the hornworms and loopers and then on my brassicas in the fall and winter. I've noticed a lot less of them in the last couple years.

Kevin

I've always heard that Bt is the solution.

Or kittens (they chase the moths and eat them)

You can also do "minister of death" patrol and squash the little yellow eggs on the undersides of the leaves.

Planting very early helps too -- since kole crops are frost hardy, you can plant early (I sometimes plant seedlings the first week of April in Zone 5, and cover with some AG fleece until things warm up a little). Probably too late to start seedlings from seed now for a really early start, but maybe you can find seedlings to buy at the end of March (I sometimes drive to a slightly warmer area--as in south or lower elevation-- to get seedlings as early as I want them)

If you use netting, obviously it has to be very small openings, and no gaps. Those moths will find any little slit to get through -- I've watched them!

I've been known to go running around my yard with a butterfly net catching the moths. I don't recommend this, as more moths just fly in, and it looks very silly.

Good luck-- I hope it works for you this year!

Elisa

Moths and butterflies lay eggs on those plants which their larvae can feed upon immediately after hatching. Keep tbe adults excluded from the host plants if that is possible. Bt-K is very helpful in controlling caterpillars but please only use it if necessary. I have a pretty small garden and have no problem hand picking caterpillars and tossing them to the birds.

When necessary (extreme load of worms) I use BT, but since I started allowing plants with large clusters of tiny flowers to self-seed around my garden, I've had a good population of wasps (even coming out in mid-winter!) that eat the eggs and tiny worms of the cabbage moths. I believe the wasp is a mud dauber (but not positive). They love the flowers of dill, fennel, onions, chives, butterfly weed, sweet alyssum, mustard, broccoli... all tiny flowers that are very attractive to tiny pollinators. I still see some of the moths, but I only picked a few worms that were deep inside a cabbage last year. I sprayed BT mostly on pickleworms.

What's amazing is to come out to the garden on a warm January day and see honeybees and wasps eating from a few sturdy flowers and the wasps patrolling the brassicas, looking for bugs. I wish they also ate slugs.

What a lot of helpful information, folks. Much appreciated. 'Cause I'm a curious fellow... I'm going to screen in an area of my beds where I grow the cole crops (brassica is probably a better term!) and see how that works out. I'm going to leave half that area open as well, and apply Bt in that area so I can see the difference in the two approaches. If I can still find this thread in a few months, I'll loop back around and let you know what the outcome is.

creative guy -- great! will be very interested in the results.

One more thing -- one year I had kale growing in my main garden and in an area that is mostly a winter garden, where the soil was not as good. The worms skeletonized the kale in the winter garden area, and pretty much left the other kale alone. That let me know that I needed to improve the soil in the winter garden, so I dumped a few inches of manure on it, and the next year had no more worms! The job of the bugs is to eat the least healthy crops, so if you can think of anything you can do to improve your soil, that should help too.

The spray you used contains spinosad, a biological pesticide with similar action to Bt, but longer residual activity. To be effective, it still must be applied every 10 days, or a window opens for heavy feeding by larvae. It takes that long for a newly laid egg to ripen and hatch.

I find that it's much less trouble to use row covers, which also protect the plants from wind and grasshoppers. In early summer when pest pressure is severe, I use row covers made from tulle (wedding net), which work great on cabbage family crops.

Here is a link that might be useful: pictures of row covers

Row covers. Row covers. Row Covers. No support needed. Lay it over the plants the day you set them out, secure the base. That's it. Total success. Easy, Cheap, reusable. Effective. And organic so safe for all.

When I tried row covers/netting, it kept most of the caterpillars off but made a safe haven for whiteflies to take over the plants. I haven't figured out how to handle the white butterflies AND the whiteflies without resorting to a couple of different sprays - bt and insecticidal soap?

~emmers

I've usede a dusting of rye flour with success.