BT question

[Dewayne mater]

I just applied BT since I noticed some tiny caterpillars and some leafs with holes. The BT is left from last year and I have a question about whether it is still effective. The color of this BT formulation was dark green blackish color. The smell was not very pleasant at all. I think I remember this is how it was when first bought, but if not, will need to replace it. The package insert says don't let it freeze (check) and don't let it get over 90 degrees...it was probably around 90 several times last summer in a garage that is very shaded, but heck, it just gets hot in N Texas. Is there any way to tell if it is still good? Thanks.

[amideutch]

Dewayne, when in doubt Chuck It.Ami

[b54red]

It should be a very light tan, almost white powder with an odor that isn't that unpleasant.
Sounds like the stuff you have got contaminated or got wet somehow. I keep mine in my shed where it generally stays hot during the summer and it always seems to work when I pull it out for my fall cabbage and broccoli.

[Dewayne mater]

Thanks Ami and B54. This was a liquid version of BT with a trade name Southern Ag (brand) Thurcide BT. I'm pretty sure the color is as it was last year, but I don't remember a bad smell. May be time to chuck it and start fresh as Ami says. BTW, BT doesn't help with white flies does it?

[tjg911]

if you use it you'll know if it works!

i have bt concentrate i bought around 1994 from blue seal or agway. it is fine and i use it without any complaints. it's called 'dipel' but it's the bt for cats (not potato bt for everything else). it is a dark cream or tannish color and doesn't smell like you'd want to drink it but it is not dark and it is not a strong unpleasant odor. i keep it in the basement were it's 45 at the worst in winter typically 55 and 73 at the upper end in summer.

[beeman]

I too had a bottle of BT left from last year, but it's now a dark brown. I did try it on the Gooseberry Saw fly caterpillars, but they just chomped merrily away.
In desperation I used some washing up liquid 'anti bacterial' in a pump up sprayer. Worked a treat, they just fell off in their hundreds, all curled up.
I then repaired the damage done by spraying well with 'Compost tea'. Can't see a living caterpillar anywhere.
Perhaps we should try washing up liquid, definitely cheaper!!

[Dewayne mater]

OK, new bottle of the same brand of BT purchased. This product is supposed to be a greenish blueish color with a smell that isn't pleasant, but isn't foul. Old bottle thrown away, new stuff sprayed, catepillars doomed.

[snappybob]

I have a bottle of what I think is liquid BT but I'm not sure. It was in one of those white plastic bottles that use some sort of shrink wrap type of label. The label has fallen off and deteriorated to the point of being non recognizable. From what I recall that bottle of BT was not cheap. But now I have 3/4 of a bottle of something that's worthless. I'm going to have to be more observant about what the packaging and labeling is like on these products and send out nasty-grams accordingly. Nasty-grams in the form of email or even better, email to multiple recipients in the same company have more power that we sometimes realize. Being firm but diplomatic always seems to get the desired response. Start off by praising their product and establish yourself as an otherwise loyal customer who would probably recommend their product to friends and acquaintances. Then let them know what the problem is with their product. Sorry I guess I got a little off topic.

[b54red]

Just a little warning about the BT and tomatoes. I had a couple of different worms or caterpillars hit our tomatoes last year that BT wasn't at all effective on. It was the first time that I had tomato chompers that weren't deterred by BT. Had to resort to Sevin which worked like a charm on them. I talked to several friends in the area and they all had the same experience. We all had to use Sevin every week for a month because as soon as the rain washed it off they came back. Hopefully it was a one time thing and maybe just in our area. So far the BT has worked on the tomatoes as well as cabbage and broccoli.

[snappybob]

What kind of caterpillars were they that were ammunr to BT? Do you have any pictures or a description?

[tjg911]

Originally Posted by b54red

Just a little warning about the BT and tomatoes. I had a couple of different worms or caterpillars hit our tomatoes last year that BT wasn't at all effective on. It was the first time that I had tomato chompers that weren't deterred by BT. Had to resort to Sevin which worked like a charm on them. I talked to several friends in the area and they all had the same experience. We all had to use Sevin every week for a month because as soon as the rain washed it off they came back. Hopefully it was a one time thing and maybe just in our area. So far the BT has worked on the tomatoes as well as cabbage and broccoli.

bt should be used only if required as in hand picking wouldn't cut it, some seasons i don't use it at all cuz hand picking is effective. i grow 7-10 plants so i try to hand pick, if you have several dozen plants you could look for the frass or damage and spray that 1 plant. over use of bt as in bt corn, bt cotton and bt potatoes (i think they gave up on this one) is the surest way to make bt ineffective. i know the potato bt is a different bacteria that the 'general' bt.

be careful because bt kills all cats including butterfly cats. i let milkweed grow in my garden for it's beautiful fragrance, beautiful flowers and of course because it's the host plant for the monarch butterfly. carrots and parsley have butterfly cats on them too, just don't use bt without it being really required.

tom

[b54red]

Tom, this was not a case of bt becoming ineffective, it was a case of two new critters that loved destroying tomatoes. It still works on the usual suspects. I have been using it for around 20 years on cabbage and broccoli and have seen no diminution in its ability to stop cabbage loopers as soon as they eat a little of it. There have always been chewing insects and caterpillars that it doesn't work on. I am keeping a close eye out for that boring looper that hit my tomatoes last year. It was the most destructive pest I have ever seen on tomatoes and that includes tomato hornworms. It was small and very hard to see. The largest one was almost an inch long, thinner than a pencil lead, light green, and a looper type caterpillar. They bored tiny holes in the small green tomatoes entering the fruit and ruining them later. The only indication of their presence was the very small hole by which they entered the fruit and if you didn't study them closely you would never notice them til too late. When I finally realized what was happening I ended up having to remove almost all of my fruitset for a big portion of my tomato patch.

[tjg911]

Originally Posted by b54red

Tom, this was not a case of bt becoming ineffective, it was a case of two new critters that loved destroying tomatoes. It still works on the usual suspects. I have been using it for around 20 years on cabbage and broccoli and have seen no diminution in its ability to stop cabbage loopers as soon as they eat a little of it. There have always been chewing insects and caterpillars that it doesn't work on. I am keeping a close eye out for that boring looper that hit my tomatoes last year. It was the most destructive pest I have ever seen on tomatoes and that includes tomato hornworms. It was small and very hard to see. The largest one was almost an inch long, thinner than a pencil lead, light green, and a looper type caterpillar. They bored tiny holes in the small green tomatoes entering the fruit and ruining them later. The only indication of their presence was the very small hole by which they entered the fruit and if you didn't study them closely you would never notice them til too late. When I finally realized what was happening I ended up having to remove almost all of my fruitset for a big portion of my tomato patch.

i was referring to the wide spread use of bt in bt corn and cotton. planting millions of acres of bt anything will fail in time as insects mutate. you and i can't really have a big impact but i still try to be judicious in the use of bt.

down your way you get cats that attack your tomatoes i never experienced. here it's the thw period. if those cats are the size of the beginning sized cabbage worms we get on broccoli and cabbage then i can see how on a tomato plant it would be next to impossible to hand pick them. i picked off several from 3 cabbage plants today vs spraying bt because i can see the damage on small plants and i know where to find the cats.

[b54red]

Tom if you leave your cabbage and broccoli untreated for more than a week down here once the white butterflies appear you will find plants that look like someone took a shotgun to them. Those boring loopers I was talking about seem to be making another appearance because I found about a half dozen holes bored into one of my tomato stems on one plant and a tiny hole bored into a very small green tomato yesterday. I am going to apply Sevin. I can't afford to wait because of the experience I had last year. I already waited too long this year in attacking my aphid problem which I thought the ladybugs would alleviate. I even found spider mites heavily infesting one of my container plants yesterday and treated it. This is looking to be a very pesty year for my tomatoes. I had high hopes after the extreme winter that the pests would be sharply curtailed this year; but I'm thinking that is a fallacy. I have had one bright spot pest wise and that has been my beans which have had only a few beetles which could easily be hand picked off while picking the beans. Usually I have a good number of bean beetles attacking the leaves.