Bacillus thuringiensis, or Bt for short, is a bacteria that produces crystal like toxins. These toxins are especially harmful toward organisms in the Lepidoptera, Diptera and Coleoptera biological orders. In other words, these toxins affect various types of moths, butterflies, flies, mosquitoes and beetles. Most of these organisms are also the creatures that cause various annoyances in agriculture and tend to be the main antagonists in the never ending war between the farmer and pesky insect.
When the toxins from this bacteria are ingested into the organism there are several chemical and biological processes that are carried out, slowly killing the organism through the swelling of the gut cell membrane and cell lysis.
This has been brought to the attention of farmers, who are seeking this as an organic solution through the genetic engineering of the toxin producing genes from Bt into crops. This has also been brought to the attention to farmers around the world, as Raj Patel states in Stuffed and Starved: "In India, a key crop is Bt Cotton, which has an insecticide produced by a soil bacterium..." (134). There have been many statements as to how successful Bt has and will be against pests, undoing what the first Green Revolution did in terms of chemical synthetic pesticides that are very harmful to human health and depletion of the environment. Bt is of course "all natural," it is a bacteria naturally found in our environment.
However, there are many downsides to using Bt. Bt is just like any other synthetic pesticide in many ways. On a normal field of crops, monoculture or otherwise, there is an array of different insects that are present. When a pesticide is applied, the insects that are genetically programmed to be resilient to the "poison" in essence, will survive. These survivors will only have each other to reproduce with, thus keeping the resilient gene in the gene pool. Soon, the pesticide will be rendered useless. Much in this same way, Bt, has different levels of effectiveness on insects of different genotypes. When the genotype has progressed to full resiliency over a field of genetically engineered Bt crops, then you are once again on a "pesticide treadmill." Also, Bt contains a higher amount of toxins that are said not to be harmful to humans. I am weary of this however, because long term affects of Bt on biological systems, or even human beings is still to be foreseen. I am also very uneasy about genetic engineering in general. It is a field that is still widely unknown, with many unforeseen consequences due to a lack of knowledge of something that is very delicate to begin with.
There has been sufficient evidence and various statistics in all of our assigned reading, specifically from World Hunger, citing that even if pesticides were not used in many instances it would make no real difference in crop yields. Bt usage is a science that in my opinion has not been thought through thoroughly enough to be really effective in today's agriculture.
During my research I found a video that very clearly spells out the above information. (Found here) However, it goes into further detail about the many problems associated with Bt, and indicates a possible solution to the problem of resilient insects. Instead of a farmer having an entire field of Bt modified crops, they will instead have only a portion of that field modified and the other portion being a control area if you will, untouched by pesticide or modification. Therefore, part of the field will be a haven for all insects, and part of the field only the Bt resilient. This in turn will allow the Bt resilient bugs to mate with the non resilient bugs of the adjacent area keeping a stable gene pool with much diversity. Unfortunately however, many farmers do not want to sacrifice part of their field to be in their eyes most certainly devoured by insects.
I was first intrigued by Bt during the readings for February 6. World Hunger made claims that it was still in the brainstorming stage, however Stuffed and Starved clearly noted that it had obviously passed that point, which is understandable because World Hunger is a slightly older book.
Interesting: (page on controlling of the Gypsy Moth in New England through this process)