will BT kill the good earth worms ?

My late lettuce crop is being devastated by green worms and black things that look like droppings. I read that loopers are green caterpillars that make green droppings but the droppings on my lettuce are black, abt 1/16th to 1/8" in size. I can't find any pictures of the droppings on the web at the moment.

I have read about BT, white or wheat flour sprinkled on the leaves, and row cover.
WILL THESE METHODS KILL EARTHWORMS? Don't want that.

Also, what kind of row cover and how to apply?

Our conditions right now have been, for the past month, wet, rainy, Autumn climate in upstate NY.

I have read about other non-toxic (to humans) treatments, such as flour sprinkled on the leaves, and row cover.

thanks for any help you can provide.
katt

From what I understand, Bt won't kill beneficial insects. It mostly targets caterpillars and some beetles. If you have a butterfly garden(or like butterflies), then I wouldn't use it since butterflies have to be caterpillars first. There are quite a few beneficial beetles, especially in the compost pile(beetles assist in breaking down organic material). Bt breaks down within a week(or so), so keep that in mind when composting plants that have been treated.

[RANT]Insecticeds, herbicides, fungicides, etc. are designed to kill living things. It is far easier(and healthier) to make an insectary in your garden, which provides habitat for beneficial insects throughout their entire life cycle(it probably won't look pretty). When you move from a biocide regimen to more natural methods of pest control, it can take as long as 3 years to regain this balance. Either way, you're going to have some crop damage, and even with the most destructive of pests, your entire crop may not be wiped out(one or two plants may look funky, but they'll still produce..of course with leaf crops, any damage is less food).

Other methods of controlling pest insects are planting at the right time of the year(so you harvest before pest insects are an issue, which I have to do with tomatoes and stink bugs), planting trap crops(again, stink bugs are my biggest issue, so I make sure to have plenty of sunflowers between the stink bugs and my sweet 100's...yes, they pretty much travel the same path year after year...it's amazing), and interplanting(having the same crop NOT planted next to each other does confuse insects, and it's highly suggested in the ANSFG book) along with planting a different crop after you harvest a square(also in the ANSFG book). They all work, but it does require a fair amount of research on your part(your cooperative extension office should be able to help). There are books on these subjects, but the USDA/Cooperative Extension offices have plenty of free information, along with other internet sources.[/RANT]

ok that's very helpful, thanks. Sounds like the BT won't harm the earthworms.

Can you, or someone, comment on the use of flour harming beneficials like earthworms? i want to get out there today and do something right away.

Also, the cost of row covers defeats the purpose of growing my own--25 bucks can buy me a lot of lettuce.

Will either BT or flour harm the seeds themselves?

I just planted another few rows and hope the weather holds for the 6 wks needed for lettuce.

Katt

katt.
I'm happy someone has answered your question as I did not know the answer myself.
Glad you are interested in the earthworms. Have you thought anything about compost worms? I am finding it a fascinating subject.

kattkandu wrote:

Also, the cost of row covers defeats the purpose of growing my own--25 bucks can buy me a lot of lettuce.


Katt

At our transfer station (politically correct for 'the dump' we have a little house called the Treasure Chest, where folks bring things that they don't need anymore, that others can take for free. I've heard that there are sheer curtains there a lot. They would make great row covers. If you don't have a Treasure Chest in your area, maybe a church thrift shop or Craigslist may have some sheers or netting.

CC

great idea, sheer curtains, thank you. they are, however, made of synthetics. May not be an issue if they are washed a few times and don't break down in the garden or leach out in the rain.

can anyone comment on the use of sprinkling flour on the plants as i posted earlier? it hurts caterpillars' intestines... one might guess it would also hurt earthworms?

katt

I have zero information on using flour to control pests, usually it's people trying to keep pest insects out of flour. Until I (personally) found more information on that, I'd probably not use it since it does seem to attract other insects.

Spraying Bt on seeds will do nothing for the emerging plant. You have to spray Bt on infected leaves(both sides) in order for the pest insect to eat the Bt(yes, even with Bt, you will have some chewing going on). I guess if you were worried about something like cutworms mowing down seedlings, but even then you should spray the Bt on the seedling(and the seedling will more than likely still be destroyed anyway), not on the seed itself.

Probably the best thing you can do for immediate relief is to hand pick caterpillars as you see them and either feed them to chickens(if you have some), drown them in water, or smash them if you're so inclined(and angry). You may have to go out at night also to find all the caterpillars.

Floating row covers can also help, and they can last many seasons if you treat them well.

thanks, "Unmutual." I meant, does the BT kill or hurt or poison the seed or cause deformed seed or make the plant's future seeds impotent?
thanks, k

i also just found tiny black worms on my brocolli rabe. they are abt 1/16" long or smaller and very thin.

i would love to pick the poor little things off if i had all day but i do have a job and really can't spend that kind of time. i might have to go w the Bt as much as i hate to/it's against my principles to kill things...i do so every time i get in the car and zillions of bugs hit my windshield.

i am assuming the Bt will kill both the loopers/caterpillars and the tiny black worms? too bad it doesn't kill the stink bugs, i have a lot of them this year too.

it's too late to plant sunflowers as a diversion crop.
is it too late to plant soy or millet? can i use that as a cover crop and leave it in for the winter?

thanks, katt

A little More on BT, and here is the entire article: http://www.env.gov.bc.ca/epd/ipmp/publications/fact_sheets/bt.htm

Does BT Harm Earthworms, Honeybees or Other Beneficial Species?

Each BT strain infects a relatively narrow range of species. Studies have shown that predatory insects, such as lady beetles, are not at risk if they eat an insect that has been infected with BT. BT does not infect earthworms, nor does it kill honeybees or many other species of insects. BT is an excellent choice for control of many pest caterpillars because it does not harm predatory insects, birds, snakes and other animals that keep pest numbers low in the yard and garden.

great, thanks much. will check the article. I am very pleased with this site, you've all been so helpful and responsive!
It just stopped raining here, we'll have one day of clear weather before more rain this weekend. It's been raining for a month so it's been a challenge for a novice like me to get fall crops in. I wonder if the rain has something to do w the explosion of the loopers, hornworms, and other caterpillar-type creatures. But the rain has helped with other things, i don't have to water my compost, and i shut off my automatic watering system.
katt

llama momma wrote:A little More on BT, and here is the entire article: http://www.env.gov.bc.ca/epd/ipmp/publications/fact_sheets/bt.htm

Does BT Harm Earthworms, Honeybees or Other Beneficial Species?

Each BT strain infects a relatively narrow range of species. Studies have shown that predatory insects, such as lady beetles, are not at risk if they eat an insect that has been infected with BT. BT does not infect earthworms, nor does it kill honeybees or many other species of insects. BT is an excellent choice for control of many pest caterpillars because it does not harm predatory insects, birds, snakes and other animals that keep pest numbers low in the yard and garden.

but beware, lady beetles and other beneficial may be killed if they are hit with bT when they are in their worm stage.