The leaves on my b. sprouts have various size holes and some shredded-looking leaves but I've never found the culprit(s) -- is there any "protection" to use? Without finding any bugs, etc., would it do any good to spray a bug killer? Any recommendations?
Without knowing what is the muncher, you may not be able to fix the problem. Caterpillars are a top problem with cole crops in the fall, and Dipel (Bt) works for them but is safe for us. Slugs/snails are another possibility; if it's them, you can scatter some iron phosphate (Sluggo) around the plants.
Sluggo Plus has spinosad, which is highly toxic to mammals. (Bees, too, but when broadcast as granules isn't really a threat to bees and other beneficial insects.) So if you have dogs or cats in your garden (or young children), you don't want to use Sluggo Plus.
Iron phosphate is also toxic to mammals if you ingest it, but you have to eat a *lot* to get seriously ill.
Like I said, I haven't been able to find the culprit(s). I've had snails in other areas and have put out Sluggo Plus, which I guess is working, but all the snails I've found have been picked up and put into a container of saline solution and dumped in the trash. I have Bt but evidently it has to be used on the munching party...
You don't have to spray the offending critter with Bt, but they do have to eat the plant. With cole crops, sometimes it's hard to get a spray to stick. A spreader-sticker can help and you do have to repeat the application every few days.
A spreader-sticker is an adjuvant that helps the chemical spread out evenly and stick to the leaves, so what you spray is more effective and you can use less of it. You can buy commercial spreader-stickers (like Biolink Spreader Sticker), or you can make your own. A small amount of castille soap will work but you really don't want to overdo it.
I had searched for my culprits early in the AM ---- but yesterday was out there later in the day (sweat time!) and found many poppa, mama and baby green cats that I promptly picked and squashed! It's almost time to go out there again for that routine...
I'm ready to start spraying all my brassica seedlings, in my brand new sprayer. I'd rather not shift from one thing to another with this tank, and I'm asking for your recommendation of the ONE spray that'll go the furthest in controlling the wormies.
My first mind is to spray them all down with the Bt, then cover the plants with the floating row cover, then follow that with the perforated hoop when the temps start dropping (actually, when the winter winds start blowing, cause that does more damage to my veggies than the dropping temps in my yard...)
For cabbage worms, etc., I would use Bt plus the spreader-sticker -- they have to go in the tank together anyway. Other than slugs, that's really the only pest I have to deal with this time of year, so that's only what I do. If there's something else causing a problem for you you might need to do something else.
I don't cover my cole crops. They really don't seem to care about the cold; but I don't have the wind you do.
I keep multiple tanks and I try to get them all the same model so when parts break I can mix and match to get a working unit. I have a very small one for Bt, a big one for Round-Up (yes, I use Round-Up sometimes), and then big ones for copper, lime sulfur and horticultural oil for my fruit trees. I haven't needed any other sprays just yet.