Consumers are willing to pay more for pesticide-free fruit, vegetables, and dairy products and therefore organic food sales are booming. Consequently, biotech based pesticides are becoming viable alternatives to chemical pesticides, as for example a biocidal product of plant origin that can combat insects as well as fungus and bacteria would find ready acceptance in farmers (for crop disease and pest control). In some case, it could be grown by the farmers themselves and the seeds can be turned to organic pesticides. Or take the case of a special form of yeast formulation when sprayed on fruits before they are transported to selling points can keep the fruits fresh. In short, biotech pesticides tend to harness nature for solving health problems of agricultural crops.
Pesticides of natural origin obtained from animals, plants, bacteria, and certain minerals are called biopesticides. These substances used for pest control in crops, are soil and ground water friendly, hence environment friendly and cause no harm to foods, and therefore consumer friendly too. And the farmer gets a spot in world organic produce markets.
The biopesticides currently available, can be categorized into three groupings, namely microbial pesticide, plant incorporated protectant or PIP, and biochemical pesticide. Let's analyze a bit more about these categories.
Microbial biopesticides: Microorganisms as for example bacterium, fungus, virus or protozoan are reckoned as microbial pesticides if they have the ability to target specific pests.Bacillus thuringiensis, or Bt together with its subspecies and strains constitute an example of microbial pesticide. It is erroneous to think that microbial pesticides are something new. In fact omnivorous leafroller and grapeleaf skeletonizer that attack the larval stages of moth have been in the market since the 1950s. AgraQuest Inc, a California based biotechnology company has been the market leader in making microbial pesticides with several products as for example, for the local vineyards it supplies a product constituting a strain of Bacillus pumilis for controlling powdery mildew and another product with a strain of Bacillus subtilis for controlling Botrytis and sour rot.
Plant-Incorporated-Protectants is biopesticide produced by plants consequent to adding a genetic material to the plant. In other words, external genes and enzymes are introduced into a plant's genetic material for converting the natural plant constituents into biopesticidal substances referred to as PIPS. Usually the incorporated genetic material had produced a natural pesticide in another organism and is now being put into another plant. PIPS that have been registered with regulatory authorities have been Bt toxins, as for example Bt Cry 3A and PLRV virus resistance gene for potato crop, manufactured by Monsanto; Bt Cry 1Ab for sweet corn manufactured by Novartis; and Bt Cry 9c for field corn, made by AgrEvo and many more Bt toxins
Biochemical Pesticides: Biopesticides carry out the function of pest control in crops by using non-toxic mechanisms such as using natural scents called pheromones that overstimulates the males and makes them disoriented, and so they can't find the females for mating ----and hence there is no more next generation of pests. That apart, there are scented plant extracts that attract insect pests to traps. In India for instance pheromones are used as tools for monitoring Helicoverpa armigera and Spodoptera litur as well as pests in cotton, tobacco, rice and sugarcane and also as a suitable pheromone lure.
Biopesticides have a localized footprint too. For instance, in India there are some biopesticides which may not have international regulatory approvals, but are nevertheless found effective for the local climate. The Indian system of medicine is called Ayurveda. Extrapolating this system of medicine to cater to the health needs of plants several biopesticides are in use.
For example, Adathoda kashayam and Pudina kashayam are used for treating leaf folder, bacterial leaf blight and helminthosporium leaf spot in paddy and vegetables; neem seed extract is used in all crops to counter leaf folder, aphids, jassids, fruit borer and stem borer; garlic arkam is used for combating leaf folder, bacterial leaf blight and helminthosporium leaf spot in paddy; andrographis kashayam and sida kashayam for treating aphids and borers in brinjal and ladies finger; cow's urine arkam and sweet flag arkam for use in paddy, ladies finger, and chilli for treating bacterial leaf blight and helminthosporium leaf spot, vein clearing disease and fusarium wilt.
Advantages of biopesticides
In comparison to chemical pesticides, biopesticides have several advantages such as:
• Biopesticides cause no damage to the environment nor are they detrimental to plant and fauna.
• Biopesticides do not have the same toxicity as chemical pesticides
• As compared to chemical pesticides, only small quantities of biopesticides are required.
• Biopesticides when used, decompose fairly rapidly.
• Crop yield are not affected by biopesticides, as they have beneficial effect on plant morphology and physiology.
• Biopesticides are targeting specific, meaning they only affect the intended pest and organisms closely interrelated. Besides, biopesticides are harmless to birds and poultry animals as well.
• The use of biopesticides results in substantial labor cost savings.
• Biopesticides being of natural origin mutates unlike chemical pesticides.
• Overuse or misapplication of chemical pesticides can cause havoc unlike biopesticides. For instance, in developing countries pesticides are responsible for causing 25 million cases of occupational pesticide poisoning.
It is important to know the mode of action of a biopesticide as compared to traditional pesticides prior to using it. For instance it may take anywhere between 2 to 10 days to eliminate an insect pest. A biopesticide cannot be considered as non-toxic because it is natural in origin, but can generally be considered only as less toxic. In tackling pest control problems in an environmentally responsible way these products fulfill unmet needs in the domain of weed and disease control.
Perhaps emphasizing the importance of agrochemicals in general and biotech agrochemicals in particular, the biopesticide/organic database of Rutgers University's IR-4 program helps farmers locate the appropriately registered biopesticide in terms of crop, pest, and location of the farm. This support programme also helps in the registration of biopesticides for use in pest control systems.
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