Uses of Bt insect resistance in agriculture - Essay Example

Uses of Bt Insect Resistance in Agriculture Although Bt can very well stand for biotechnology as the two have been tied closely by science over the past two decades, these two letters actually stand for something that farmers across the globe have known to be a very reliable anti-pest tool - Bacillus thuringiensis. (Shelton 2008) Bacillus thuringiensis or Bt is one of nature's effective bug control devices. It is actually a kind of soil bacteria but can also be found in both living and dead insects, and on plant surfaces. (Shelton 2008) It owes its name to a town in Germany called Thuringia where Ernst Berliner got a sample from a mill where dead flour moths lie; Bt, he assumed, being the cause of their death. This remarkable finding which happened in 1911 was not the first time Bt went under close inspection; in the Far East, ten years before, a Japanese scientist who was investigating the almost instantaneous death of silkworms first discovered it. (Federal Ministry of Education and Research "Bacillus '" 2007) More than a century has now passed since Bt's discovery, and for more than half of it, Bt has been used as a natural insecticide, being sprayed onto crops. (Shelton 2008) But just how does Bt work in the first place' Unlike Dichlorodiphenyltricloroethane (DDT), which has been known to be a three-letter acronym for the words notorious killer because of its infamousness in inflicting damage to organisms it should not, Bt is not a contact poison. (Bassein 2008) Bt has to be eaten first before it can poison any unsuspecting insect. B. thuringiensis has spores which contain crystal proteins or cry proteins. When ingested by an insect, the active insecticidal crystal protein or (ICP) breaks down in the insect's gut and releases a toxin called delta-endotoxin. This delta-endotoxin then reacts with certain receptors on the intestinal lining and makes pores causing the leakage of its contents and paralyzation of the insect's digestive system resulting to insect death. (Office of Biotechnology at Iowa State University 2008) The killing is a slow process that may take hours or even days. (Shelton 2008) However, it must be noted that because of the paralysis of the insect's digestive system, the insect soon stops eating. Immediately dead or not, the goal of saving the crops from mass mastication of unwanted living forms is definitely achieved. (Office of Biotechnology at Iowa State University 2008) Bt may not be as fast a killer as the conventional insecticides are, but in this ever health conscious world, speed is not the only thing to consider. Synthetic insecticides such as those whose active ingredient is DDT have been banned in many countries and for a number of good reasons. And it is because of such reasons why many farmers choose Bt over it; human safety, of course, is the primary concern. (Bassein 2008) As mentioned, Bt has been used for more than 50 years now as an effective insecticide. So far, there are no reports of it harming anyone. And the underlying reason according to experts is the fact that Bt toxins are toxic only to certain insects; truly, this is good news for bees and beekeepers alike. The rationale' The receptors which are present in the insects' guts are not found in most other organisms, in mammals, and most importantly, in humans. (Federal Ministry of Education and Research 2008) The different strains of B. thuringiensis produce different delta-endotoxins, each "catering" to a specific order of insect. The most common of Bt's cry proteins are those that belong to the Cry1 class which are toxic to lepidopterous insects (e.g. moths such as the European corn borer, butterflies). It is also the most active ingredient in most Bt-based commercial insecticides today. Other proteins belong to the Cry2 class which unlike their Cry1 counterparts, produce a single, smaller crystal per cell. This class is toxic to insects belonging in both the Lepidoptera and Diptera (e.g. flies and mosquitoes) orders. There is also the Cry3 class which poisons the coleopterous (e.g. beetles like the Colorado potato beetle, corn rootworm) insects. For dipterous insects, there is the Cry11 class, and for both the lepidopterous and coleopterous orders is the Cry5. To be able to administer the correct cry protein to a specific pest, it is but essential for farmers to have knowledge of the different strains of Bt. (Park Baoxue Leah federici Brian 2008) The luxury of specificity is something that DDT failed to offer. Insects are not the only ones at risk once the lethal chemical gets airborne; in fact, even with its great speed, the fastest flying bird in the world was not able to escape its poisonous effects. For a period of time, parenting peregrine falcons watched their eggs break as they tried to incubate it - all because DDT caused their shells to be thinner. In 1971, the time came in Wisconsin to finally ban the infamous insecticide. (Wisconsin Department of Natural Resources 2003) Sadly, falcon reproduction is not the only one affected by DDT, but also humans as well. Studies have shown that the long term exposure to the chemical can lead to many reproductive disorders. (Bassein 2008) Such adverse effects to the living make it no wonder how Rachel Carson can write the eye-opening and inspiring Silent Spring in 1962. It is also no wonder how she could be an advocate of the use of Bt as a natural insecticide. (Shelton 2008) With its eco-friendly qualities, many people as Carson have learned just how much better an insecticide occurring in nature replaces a micro monster such as DDT. In fact, the people's belief in Bt has taken them not only to the creation of Bt insecticides but to the cultivation of Bt crops as well. With the aid of bioengineering, Bt has become a part of the defense system of certain crops saving growers the millions that they used to lose in their past battle with pests. In 2006, 102 million hectares of genetically-engineered crops have been produced worldwide with about a third of it involving cotton and maize genetically altered to produce their own ICPs. (Wolfenbarger Naranjo Lundgren Bitzer Watrud 2008) Bt maize, cotton and potatoes are among the Bt-crops commercially available today. (Office of Biotechnology at Iowa State University 2008) But as these genetically-modified organisms (GMOs) grow, both in the field and in the market, concerns for their safety also develop. And truly, there are many kinds of people whose concerns must be properly addressed: environmentalists, entomologists, parents, teachers, young, and old. Thankfully, recent studies shed some light on the matter. "A thing of beauty is a joy forever," and so the saying goes. Something as adored as the monarch butterfly is, as proven, worth the time of many people for them to seek the clarifications to an issue that Bt toxins can dangerously affect the lovely insect. While it is true that the larvae of monarch butterflies could be harmed by Bt maize pollen if ingested, it was found out that only a small percentage of the butterfly's population gets in contact with the maize, and therefore does not endanger it. (Federal Ministry of Education and Research "Bt Maize . . ." 2008) In the course of nature, the Bt crops will eventually pass on to the soil its Bt toxins and concerns have been raised as to how it will affect it, as well as the other microorganisms present in it. Scientists discovered that in the rhizosphere (the part of the soil affected by the roots), the trusty fishing companion that is the earthworms were unlikely to suffer from any bad effects of the little amount of Bt toxins present in it. (Federal Ministry of Education and Research "Bt Maize . . ." 2008) Especially now, for example, that Bt maize has lower levels of Bt toxins as compared to the first commercially grown maize that came out. Also, the presence of Bt toxins in maize plants now can only be located in parts of the plant where the pests attack (e.g. the roots only), therefore, reducing even more the Bt toxin content of the Bt crop. (Federal Ministry of Education and Research "Bacterial . . ." 2008) The thought of buying something beneficial for you and your loved ones' health while in reality is otherwise is one horrid thought indeed. When such a mental visual comes to mind, anxiety is bound to follow. That is why to relieve the many of such head-aching concerns, the European Food Safety Authority since 1998, has approved the MON810 Bt maize as safe for cultivation. As a matter of fact, several millions of acres of farming land have witnessed the growth of MON810 Bt maize for years now, with the yields having been used primarily as animal feed. Until now, no report has been made regarding any bad effects of this Bt crop on animals, the environment and especially, humans. (Federal Ministry of Education and Research "Bt Maize . . ." 2008) The right to choose, however, has not been waived in any way. People who still are not comfortable with GMOs still have the freedom to use naturally grown crops, whether they be individuals or countries who do want to import such. That is why some farmers make it a point to try and separate Bt crops from non-Bt crops throughout the production and handling processes. (Office of Biotechnology at Iowa State University 2008) For no matter how pleasing all this news is to the ears of any caring grower, it is still the consumers, in the end, who will determine the success of these products and the efforts behind them. Works Cited "Bacillus thuringiensis Profile of a bacterium". GMO Safety: Genetic Engineering - Plants - Environment. Federal Ministry of Education and Research. 04 Apr 2007. 13 Aug 2008 "Bacterial arsenal to combat chewing insects". GMO Saftey: Genteic Engineering - Plants - Environment. Federal Ministry of Education and Research. 29 Feb 2008. 13 Aug 2008 "Bt maize: Is it safe for humans and the environment'". GMO Safety: Genetic Engineering - Plants - Environment. Federal Ministry of Education and Research. 14 May 2008. 13 Aug 2008 Emma, Bassein. "Lives on the Line: DDT, Malaria, and Infant Mortality". Earth, Atmospheric, Planetary Sciences. Massachussets Institute of Technology. 2008. 13 Aug 2008 Park, Hyun-Woo Ge, Baoxue Bauer, Leah S. and Federici, Brian A. "Optimization of Cry3A Yields in Bacillus thuringiensis by Use of Sporulation-Dependent Promoters in Combination with the STAB-SD mRNA Sequence". PubMed Central. October 1998. 13 Aug 2008 Read More