I've been very glad to discover spinosad, effective against plants that eat veggies, but not against their predators unless, sometimes, sprayed directly on the predator. In my research I've seen recommendations to apply it every 4 to 5 days during, for instance, flea beetle season.
But then I found an article on a California university web site about thrips that said it should be applied no more than twice a season. The label on Bonide's Captain Jack product has various maximum applications for different veggies, from 4 to 6 times a season.
If spinosaid is a biological agent affective only on veggie eating insects, what's the harm in applying it more often? And why the different recommendations about max number of applications?
TIA
LAS
Conflicting messages re spinosad
according to a study by the university of minn. "The topical acute activity of spinosad against honeybees is less than 1 µg per bee which places spinosad in the highly toxic to bees category of the EPA." for this reason alone i would not use it.
the quote was taken directly from a UofMN study.
I have read that it is toxic to honey bees only when applied directly on them, or when they encounter it while still wet.
LAS
at the rate the honeybee population is declining why use something toxic to them, even if it is only when it is wet (and i did not see that mentioned but will research it)
There are better ways to deal with flea beetles than spinosad and I'd recommend you reserve it for extreme control. We use neem as a first line, and alternate with spinosad, but try not to use that either. I've not read you are limited to twice per season but you are limited to four or six times. Don't take this as advice 'cause I can't quite remember. Regardless of safety levels with organics, one assumes when using organic pest control, the ultimate objective should be using no chemical control organic or not. It sounds like you might benefit from row covers. What crops are you trying to grow that require spinosad? Seeing your location I can imagine that you might only have one chance to grow out a crop. I may have a leg up on you there but, by the same token, I have three to five generations of pests while you have only one or two. It takes creativity to get the goods from garden to table.
Laurel
Thanks for the responses, but flea beetles have literally destroyed my cole crops. I have to do something or give up veggie gardening. Spinosad seems to be doing some good on purchased plants I got to replace, but their older leaves look like a sieve. And in past years earwigs have destroyed my delphinium. This year I've managed to get past the point where they can be killed by too much defoliation.
Cole crops do not require pollinators so perhaps you will consider row covers. They are cheap and reusable. Perhaps it is too late for you to seek alternatives this year but maybe look into it for next year?
Ditto on the row covers for cole crops, LAS.
As for me, flea beetles seem to go after my eggplants but I've never had them on cole crops, ever. However, if you want to use spinosad I doubt you'll be encountering bees on your cole crops, no flowers to attract them until the following year when they go to seed. Are you sure flea beetles are eating those plants? Or could it be worms, which are much more prevalent on those crops?
Shoe
Thanks for your responses, MarypopLaurel and Horseshoe. I've tried row covers, especially on vulnerable crops such as arugula and turnips. They have to be pinned down absolutely "airtight". Not practical for a large garden. As for Horseshoe's observation about not getting them on cole crops, well, that really emphasizes the fact that there are a number of kinds of flea beetles!! I also have them on my eggplants, though.
I don't think there's any mistaking the little bullet marks of flea beetles. Nothing like any worm damage I've ever seen. Anyway, I see the little black beetles on the cole crops and eggplant.
I am now spraying with pyrethrin (contact only) when I see them, and spinosad every seven days, since the label says you can only spray 6 times a season before creating resistant bugs.
I have not had your experience despite our infamously buggy environment. My garden is just a small kitchen garden, only about a quarter acre. I don't have any crop that requires more than fifty feet of cover. I have not had to pin my covers. Maybe you have more wind than I in Maine. Small stones, spare stakes and sticks have been effective. I have successfully conquered flea beetles, cabbage worms and squash vine borers. You must have different bugs than we do. Nothing likes arugula except us. I use it as a green mulch. It volunteers in Spring, allows for harvest until about now, and then reseeds like crazy for a new crop through Fall. Good luck with your plan. It's all a learning experience.
"Bullet marks". That's the PERFECT description of those flea beetle's damage, LAS. No doubt you must have some delicious cabbage, and tender I bet. (I'm jealous!) :>)
Shoe
I had flea beetles completely destroy my turnips two seasons ago. I left them alone so their predators could build up a good population, and I haven't seen a flea beetle since!
It has been my experience during the 59 years I've been gardening, that when predator/prey are in the correct relationship, the damage done is minimal.
Honeybee i so agree with you !!!!
Well, flea beetles have made it impossible to grow arugula or turnips for many years. I wasn't spraying anything regularly (rotenone when potato bugs showed up and pyrethrin/rotenone on squash when squash bugs showed up). Flea beetles also badly damaged cole seedlings and eggplant. So waiting for natural predators to show up didn't work, although I wasn't doing it consciously.
I've since figured out that the maximum number of applications for Spinosad varies by plant because it is to prevent resistant varieties of bugs from evolving. Different plants have different bugs and different rates of evolution. It does not imply that it is harmful to anything not listed.
There are a number of kinds of flea beetles and other people here in Maine have reported bad problems this year, so I expect "flea beetle" problems may vary significantly from place to place.
LAS, I wonder if you'd have better luck with a Neem product. It basically interrupts the reproduction stage of insects/bugs so spraying it early on will reduce further hatchings the rest of the season as well as help cut down on the number of eggs/larvae, etc that might overwinter in soil.
Shoe
The problem with that is that if the seedlings are quite small, Neem can kill them. And if I don't catch the problem early, and the seedlings are substantially weakened, Neem can also kill them. I've had that experience a number of times. I wish Neem didn't have that effect, because I find it attractive.
Well, I have been lucky enough that Neem hasn't killed any plants I've sprayed it on. The neem products vary from manufacturer to manufacturer, varying in strength, varying in how it is processed, etc. I've been using Bio-Neem by Safer's.
On early plantings I keep flea beetles away with talcom. It acts more as a repellent or an "irritant" and needs to be applied again if washed off.
Sure hope you find a way to get rid of your flea beetle problem. I feel for ya. It sounds like a battle I have with squash bugs each year, no fun!
shoe
Eeewww!!! Squash bugs are the worst! Ugly! I fight them by hand squashing and scraping off eggs.
LAS14 - I'm wondering what kind of fertilizer you are using. Personally, I use only organic fertilizer once the transplants are in the ground. My soil is filled with all kinds of creepy crawlies. I'm convinced it's these critters that keep down the "bad bugs" that eat our plants. Chemical fertilizers make it hard, if not impossible, for such soil life to exist.
It also takes several seasons for "good bugs" to build up in the soil.
Tilling the soil also disturbs the soil's structure, killing off good and bad soil organisms. I try to disturb the soil structure as little as possible.
Each year I add a layer of compost and earthworm castings to each bed. When seeds are sown, I dig a shallow trench, add fertilizer, stir it in, and plant the seeds. With transplants, I dig a hole, add fertilizer, blend it well with the surrounding soil, add my transplant and fill in the hole around the plant.
My "bug killer" is an index finger and thumb :)
Every two years we dig in a truck load of composted cow manure along with greensand and rock phosphate. We leave half the garden fallow and plant with buckwheat. Each spring we dig trenches to form raised beds. The only chemical fertilizer I use is a bit of Osmocote with individual seedlings.
LAS14 - your garden certainly seems organic enough. I'm at a loss as to why flea beetles are such a pest. Do you have neighbors nearby that grow vegetables? Maybe the beetles are flying in from there.
We have a large toad/frog population, and I think they help keep down pests. We didn't set out to have a "frog pond" but when my hubby dug out an area in the front yard for me to plant some perennials, it filled up with rain water and the frogs moved in. I decided frogs were more important than perennials.
We don't have any close neighbors, and the ones that are closest don't grow veggies... I'm thinking location may play a big part. People in the Northeast Gardening forum are reporting lots of flea beetle and earwig problems. From what you've said you just don't have the same kinds of flea beetles that I have.
Horseshoe, mightn't Spinosad be better than Neem because it only kills insects that eat plants, not the others, that might be beneficial?
Also, how long should one wait to determine whether or not an application of Neem has worked? 2 days? a week? (A week of no treatment would be fatal to some of my seedlings, I'm afraid.)
TIA
LAS
LAS, it seems to me in your case of flea beetle infestation you could use both. I know of no beneficial that preys on flea beetles so I doubt you'd run into hurting any. If I use neem I use it during low beneficial activity as well as when I see few, if any, beneficial bugs to begin with. I'm a wait-til-the-last-minute sprayer anyway and then first choosing more benign products to use before pulling out any big guns (which is seldom). I think the biggest bazooka I've used (and used sparingly) would be pyrethrin.
With neem it doesn't kill on contact (as you probably already know) but, depending on the pest, tends to either disrupt their reproductive cycle, their wanting to eat (so they starve), and/or their egg hatching ability. Grasshoppers and leafhoppers are said to stop eating immediately when sprayed with neem. Other insects/bugs will take longer OR simply have an inability to move to their next stage of growth or be able to reproduce.
If you don't want to try neem then Sevin dust will work pretty well. It's not considered "organic" but it has a short active period and degrades quickly. Other than that I believe kaolin would be a good product to use, helping to reduce their numbers because they will refuse to eat the crops that are sprayed with it.
shoe
Next year, given that I grow my own seedlings, and can't get them really big before planting time, I think I'm going to spray Neem on the grass all around the garden at planting time. I've read that that's where the flea beetles hang out when they're sleeping or doing whatever they do between meals. Then, if the seedlings aren't too weakened, I'll try it again later on the plants. Otherwise I'll go for Spinosad. I do use Pyrethrin but only directly on visible beetles, as I understand that it must hit the bug to kill it. Thanks, all, and wish me luck!!
LAS
Okay, I think I'm confused. I know that spinosad is used to kill fleas on dogs, and fire ants (by contact and ingestion), so I don't think it kills only plant eating bugs. Anybody got better or more current info?
BTW ,LAS14, I had to giggle at your saying "effective against plants that eat veggies,". I had the best image of a stalk of Brussels Spouts munching it's way along a row of squash :))
LOL!!! There's my rice pudding brain again.
Do you know where you saw that Spinosad is effective against fleas? (I don't know what fire ants eat for a regular diet.)
It's used in the flea med Comfortis;
http://www.comfortis4dogs.com/
I'll get back on the fire ants...
Well, I can't claim to understand everything below, but it does look like, ultimately, the flea is eating the spinosad. So I guess I'd have to say that spinosad is effective only on, "veggie eating insects or those that eat blood-of-animals-that-have-eaten-a-pill." Now I don't know why beneficial insects don't suffer from eating spinosad-dosed insects, but studies have been done about that, and apparently they don't.
From the Comfortis label
"Spinosad is a member of the spinosyns class of insecticides,
which are non-antibacterial tetracyclic macrolides. Spinosad contains two major factors, spinosyn A and spinosyn
D, derived from the naturally occurring bacterium, Saccharopolyspora spinosa. Spinosyn A and spinosyn D have
the chemical compositions 2-[(6-deoxy-2,3,4-tri-O-methyl-α-L-mannopyranosyl)oxy]-13-[[5-dimethylamino)-
tetrahydro-6-methyl-2H-pyran-2-yl]oxy]-9-ethyl-2,3,3a,5a,5b,6,9,10,11,12,13,14,16a,16b-tetradecahydro-14-methyl
-1H-as-Indaceno[3,2-d]oxacyclododecin-7, 15-dione and 2-[(6-deoxy-2,3,4-tri-O-methyl-α-L-mannopyranosyl)oxy]-
13-[[5-dimethylamino)-tetrahydro-6-methyl-2H-pyran-2-yl]oxy]-9-ethyl-2,3,3a,5a,5b,6,9,10,11,12,13,14,16a,16btetradecahydro-
4,14-dimethyl-1H-as-Indaceno[3,2-d]oxacyclododecin-7,15-dione, respectively.
LAS14 - I didn't know flea beetles hung out in grass. Maybe that's why mine disappeared. Hubby and I have dug out all but a small area of grass and covered everything with leaves.
The small area of grass that is left is on our "to do list" - we plan on planting more vegetables in that area next year.