The jail garden has been hit hard by most likely cabbage loopers...they're really working on the plants. The plants are still young and most of them can overcome the damage (some are goners) *if* we can put a stop to the worms.

One of the ladies picked up a bottle of Fertilome Caterpillar Killer Bt spray the other day and all the plants were sprayed with it. It seemed to have no effect as several days later the plants were worse off than before spraying.

In looking at the bottle I'm wondering if it is an old bottle. The label is kinda pale green and lists it as having 15-percent Bt spores and associated "stuff" as active ingredients. It has no "OMRI Listed" label on it. Looking online I mostly see a different bottle with a darker green label. This newer-looking bottle states over 98-percent Bt and other "stuff" as active ingredients.

Did we get an old, weaker version of Fertilome Bt? Should we look for a different brand/type???

Help!!!!!!!

Would this be a case of "more is better"? ...or not?

Bottle that we have (15% active ingredients)...


Other bottle online (98+% active ingredients)...


(sorry for the bad, low-rez images...they were stolen off the Internet )

Is this stuff you dilute?
Maybe put more in?
My bottle of conentrate is at least a year old but still seems to work..

Both are concentrates.

The bottle we have came from a brick and mortar store and the difference in the labeling and stated percentage of active ingredients made me wonder if it might be an older bottle.

I have heard, it can lose effectiveness.

I just looked on the Fertilome website and didn't see the 15-percent version of their Bt. The University of Florida states that the liquid concentrate loses effectiveness in 2-3 years. I'm thinking I'll bite the bullet and buy some of the 98% stuff, or maybe buy a powder version that will store longer.

I rarely use Bt in a sprayer. On the rare occasions that have I used Thuricide. seemed to work ok, Disadvantage is that that you need to make up a new batch for each use. Since Bt needs to be applied after each rain event. Dipel dust or equivalent does not deteriorate when stored in the dust gun. ready on a moments notice. For me very effective on chewing larvae of moths and butterflies like Cabbage looper and Cabbage Whites

Thanks for the input, Dillard. I see what you're talking about on working strength longevity in the sprayer. Most of what I read says use it within 24 hours. Seems like the dust might be a little better at getting into the hard-to-spray spots, too. Any recommendation for a brand of dust?

What I'm finding for Bt dust appears to be called "Dipel". Is this the right stuff?

@farmerdill

Hey ed.. Dillard said Dipel above

Yes the first dust available was Dipel. The liquid form was Thuricide. Not many casual gardeners use dust anymore, but most feed and seeds will carry BT dust under several brands. Most difficult is finding a dust gun, either a pump or rotary model. A dust gun is essential for application.

I was trying to determine if Bt and Dipel were the same things...I'm "OCD-Me", remember. I confirmed that they're the same thing on some websites. I think I'm going to order some Souther Ag Dipel and go from there. I've got a duster that will work good that I got way-back-when...time to break it out!

farmerdill said: Yes the first dust available was Dipel. The liquid form was Thuricide. Not many casual gardeners use dust anymore, but most feed and seeds will carry BT dust under several brands. Most difficult is finding a dust gun, either a pump or rotary model. A dust gun is essential for application.

Thanks, Dillard. I've got two dust guns, actually. I've got an old metal pump and a new plastic one that's smaller that I got several years back and have never used. I bought the plastic one because I was having issues with the metal one. I'll have to dig them out of the shed.

Bacillus Thuringiensis is the biological poison, Dipel is a trademark. Differences among brands is usually concentration of Bt, but many will have fungicides, miticides etc

Best to use within 2 years of purchase. When you purchase a garden chemical ALWAYS write the date on it.

I was looking for Dipel on line and found this tip for using it on Planet Natural:
"Bt breaks down quickly in sunlight — apply in late afternoon or on cloudy days for maximum effectiveness."

great info here, thanks folks

This is the little duster that I have, it holds a pound of dust. I'm not sure this will work for what I need but I'll give it a try! (Of course, I've still got to dig it out of the shed and make sure age, mice, heat, cold, google-eyed-party-poopers haven't deteriorated it in some way...seals, o-rings, etc.,. I bought back in 2017 for $7.42. It's currently $10.49...

Hey guys, just a note to remind you that while BT in its different forms is a powerful deterent the different types of BT are quite specific. Each type or strain affects different insect groups. Target insects include the beetle family, the fly family including mosquitoes, and the butterfly family. It is used to kill beetles and the larvae of mosquitoes, black flies, and moths.2,3,4 Bt is also toxic to nematodes. The formula quickly knocks down spider mites, whiteflies, aphids, thrips, mealy bugs, leaf rollers and scale insects. The preponderance of evidence seems to say that honeybees are NOT affected adversely by BT. My swiss chard was being ravaged until I sprayed BT Kurstaki. In less than a few weeks this small patch was growing more than we could eat even when harvesting daily.

Great info!

HEY -- which BT is good against scale? I want to be sure I get the right one. I have hard bodied scale that I can't quite eliminate on a couple of houseplants. I tried googling and only found references such as "used against mosquitoes on a large scale." Thanks!