To kill the caterpillar stage of moths and butterflies.
Bacillus thuringiensis (Bt) is actually a naturally occurring bacterium, common in some soils, that causes disease in certain insects, most notably leaf and needle feeding caterpillars. It was first discovered in the early 1900s. They can be derived from microbes or from plants and should be handled with the same safety precautions you would use with any other pesticide. Bacillus thuringiensis (Bt) is a microbial pesticide that illustrates how natural pesticides can be safe and effective for the gardener. They seem to think that our carefully-tended plants and vegetables were planted for their benefit alone. Bt, or Bacillus thuringiensis, is an organic insecticide that is a useful addition in the gardeners' arsenal against many of these plant-eating insects. Myth at a glance. GM proponents claim that GM Bt crops reduce insecticide use, as farmers do not have to spray chemical insecticides. But GM Bt crops do not reduce or eliminate insecticides. They simply change the type of insecticide and the way in which it is used – from sprayed on, to built in. insecticide Bt (Bacillus thuringiensis). It summarizes the strengths and weaknesses of products available commercially and lists the most promising uses for Bt. The microbial insecticide Bt discussed in this publication is regulated by the United States Environmental Protection Agency (US EPA). Thus, over the last 40 years, Bt has been used as an insecticide by farmers worldwide. Organic farming in particular has benefited from Bt insecticide, as it is one of the very few pesticides permitted by organic standards. The insecticide is applied either as a spray, or as ground applications. The microbial insecticide Bt is a concentrated formulation bacterium that kills the caterpillar stage of moths and butterflies. The active ingredients are spores and toxic crystals produced by the naturally occurring bacteria, Bacillus thuringiensis. DiPel® PRO DF is a biological insecticide containing the bacteria Bacillus thuringiensis or Bt. It is used specifically for control of caterpillars which are the worm like larvae of butterflies and moths. After ingesting a lethal dose, larvae stop feeding within the hour, and will die within several hours. As an organic insecticide, Bt kurstaki is especially useful for eliminating corn earworms and those little green cabbage worms that like to infest broccoli. If tomato hornworms are destroying your tomato plants, a dose of Bt kurstaki will quickly dispatch those big green caterpillars. Bt is an organic insecticide that works by affecting the insects' digestive system. When an insect munches on a plant that has been treated with Bt, the Bt bacteria paralyzes the insect's digestive system and the insect stops feeding and expires from starvation within days.
http://www.gardeningknowhow.com/plant-problems/pests/pesticides/using-bacillus-thuringiensis.htm http://www.vegetablegardener.com/item/5344/bacillus-thuringiensis-a-natural-and-safe-microbial-pesticide http://freeplants.com/bt-organic-insecticide.htm http://earthopensource.org/gmomythsandtruths/sample-page/5-gm-crops-impacts-farm-environment/5-3-myth-gm-bt-crops-reduce-insecticide-use/ http://miami-dade.ifas.ufl.edu/pdfs/fyn/bt.pdf http://www.isaaa.org/resources/publications/pocketk/6/default.asp http://www.dnr.state.mn.us/treecare/forest_health/spraying/bt_insecticide.html http://www.americanatural.com/products/insect-animal-controls-repellents/dipel-pro-df.html http://freeplants.com/bt-organic-insecticide.htm http://freeplants.com/bt-organic-insecticide.htm
what is the use of bt spray for plants