2 acre farm: Bacillus Thuringiensis

2 acre farm

The experiences, trials, and lives on a small farm in rural Illinois.

Wednesday, July 21, 2010

Bacillus Thuringiensis

The title of this post may sound a bit scary with the Latin name but Bacillus Thuringiensis is a harmless natural bacterium also known as "BT", harmless to everything but moth and butterfly larva that is. Its toxic nature towards these creatures is why it ranks high on organic farmer's insecticide list. Some of the most destructive pests in agriculture are larva or caterpillars. Interestingly enough BT has gotten a bad reputation because it is what has been genetically modified into field corn and cotton, instead of dusting or spraying, to control the destructive larva.

In contrast Carbaryl sounds relatively harmless unless of course you know its chemical name, 1-naphthyl methylcarbamate, heck not only is it scary sounding but you can't even pronounce a word with a hyphenated "1" at the front of it. Really you can't. Carbaryl is the active ingredient in many common synthetic insecticides like "Sevin".

I bring these two up because it is interesting to me how Carbaryl comes off as relatively harmless while BT is this nasty thing associated with genetically modified organisms (GMO) and the cooperate chemical giant Monsanto. I also am talking about this now because I recently overheard a conversion at the market between a farmer and customer about “Sevin”. It went something like this:

Customer: “Did you use any pesticides on these (crops)?”
Farmer: “Only Sevin.”
Customer: “Is Sevin dangerous.”
Farmer: “No you can eat crops the same day you spray Sevin on them.”
Customer: “So it isn’t like Round-Up (an herbicide by the way not an insecticide whatsoever).”
Farmer: “Oh No, nothing like Round-Up!”

First of all you cannot even begin to compare an herbicide and a pesticide due to the fact that if both are used they are rarely sprayed at similar times. Herbicides are almost always sprayed early in the season before planting or shortly after. Pesticides are generally sprayed to protect the fruit of the crop which occurs in most cases much later. The issue with herbicides has more to do with their affects on the environment than our health. I am not saying herbicides have not been linked to health issues I am just making a point that the farmer should have pointed out how incomparable they are. He probably should have also mentioned that he uses Round-Up himself but that’s another story.

Moving on I would like to share some information from Cornell Universities’ Cooperative Extension website on Carbaryl via a series of quotes: “Carbaryl is a wide-spectrum carbamate insecticide which controls over 100 species of insects on citrus, fruit, cotton, forests, lawns, nuts, ornamentals, shade trees, and other crops, as well as on poultry, livestock and pets. It is also used as a molluscicide and an acaricide. Carbaryl works whether it is ingested into the stomach of the pest or absorbed through direct contact. The chemical name for carbaryl is 1- naphthol N-methylcarbamate.”, “Carbaryl is moderately to very toxic” , “Direct contact of the skin or eyes with moderate levels of this pesticide can cause burns” , “Inhalation or ingestion … resulting in nausea, stomach cramps, diarrhea and excessive salivation.”, “Carbaryl is lethal to many nontarget insects.”, “The destruction of honeybee populations in sprayed areas is sometimes a problem.”, and “Accumulation of carbaryl can occur in catfish, crawfish, and snails, as well as in algae and duckweed.” It goes on and on but I’m not trying to write a novel. You can find this information here: http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/carbaryl-ext.html You will find a lot more information by searching for Carbaryl Material Safety Data Sheets (MSDS) which will warn you to wear gloves and goggles when handling. You also need to seek immediate medical attention if you ingest it according to these sheets.

You will be hard pressed to find similarly dramatic information on BT. Most warnings include generalized cautions like flushing eyes with water if eye contact occurs or drinking water if ingested. I found nothing about immediate medical treatment, being toxic, causing burns, or killing bees. Most of the warnings are the same thing you would do if you got sand in your eyes or mouth, flush it out.

This very long post basically boils down to a few simple morals. 1.) BT is not a big bad nasty chemical. In no way do I agree with Genetically Modified Seeds or GMO's (such as those used in Corn, Soy, Cotton, Canola, etc.), nor do I use or promote them; I am simply referring to BT in its natural form. 2.) Educate yourself. While most farmers at the market are generally honest and knowledgeable not all of them are. Now, more than ever, we as consumers need to educate ourselves and be aware.

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Blogger grower said...

The BT is a natural pesticide in horticultural, but when is used by planes for butterfly larvaes in forest, like Quercus Suber (cork) in Sardinia Ile, is very dangerous to all species of butterflies!

July 22, 2010 at 10:34 AM  
Blogger Nathan (2af) said...

I am not familiar with this practice. Somehow it doesn't surprise me at all that people have found a way to abuse this natural substance. I personally use it quite minimally because it does carry the risk of killing caterpillars that are harmless. This year to date I have applied BT around three times. Which would be about a whopping 12 ounces by volume. Thanks for the input and information grower.

July 22, 2010 at 12:11 PM  
Anonymous Katelyn said...

My husband and I are growing our first organic garden (and second garden ever), and we have been reading about organic pesticides recently, as we lost our squashes and many corn to squash and European corn borer. Thanks for your post, it was nice and easy to read!

July 23, 2010 at 8:50 AM  
Blogger Nathan (2af) said...

Katelyn - Glad you liked it! I didn't mention it in this post because it wasn't relevant but I nearly always try Diatomaceous Earth before anything else. It is a form of silica (sand) that will kill a wide variety of pests. It wouldn't have helped your corn or squash much but it is an awesome pesticide for many things.

July 23, 2010 at 8:34 PM  

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