Biopesticides are natural substances, such as microbes, Bt bacteria, plant extracts, fatty acids or pheromones. Their use is growing rapidly worldwide, and are in demand for their value in IPM programs to improve yields and quality along with their low impact on the environment.
Biopesticides offer additional benefits, such as novel and complex modes of action for resistance management to extend the shelf life of conventional pesticides. They also add flexibility in a traditional agricultural operation with reduced pre-harvest intervals to manage waste from exported products, and shorter re-entry field times for workers, which reduces labor costs.
Read on to learn more about the history of biopesticides, current EPA registered products, their benefits and barriers to adoption, the science behind biopesticides, their rigorous registration and field development process, and how they fit best into one Pest control program
Biopesticide Definitions and Registration Process
The Environmental Protection Agency defines biopesticides as certain types of pesticides derived from natural materials, such as animals, plants, bacteria and certain minerals. Canola oil, garlic, peppermint oil and baking soda, for example, have pesticide applications and are considered biopesticides.
Biopesticides are considered an effective pest control option for the production of organic crops. However, they are increasingly recommended and used as components of integrated pest management programs in the production of high value special crops such as fruits, nuts, vegetables, grapes, ornamental and turfgrass.
By the end of 2008, there were approximately 245 biopesticide active ingredients registered used in products as varied as deer repellent and applied on the skin, insect repellents, as well as products for pest control for commercial farming. As natural pesticide materials are identified and adapted for use, the number of registered products will continue to grow. Currently, the EPA recognizes three major classes of biopesticides:
1. Microbial pesticides consist of a microorganism (eg bacteria, fungi, viruses or protozoa) as the active ingredient used to control pests. The microorganism can be produced naturally, whether living or dead, or modified by genetic engineering. Microbial pesticides can control different types of pests, although each separate active principle is relatively specific to the target pest [s]. For example, there are fungi that control certain weeds, and other fungi that kill specific insects.
The most widely used microbial pesticides are subspecies and strains of Bt, Bacillus thuringiensis. Bt was first recorded by the EPA in 1961. Each strain of this bacterium produces a different blend of proteins, and specifically kills one or a few related species of insect larvae. While some strains of Bt moth control larvae found in plants, other strains are specific for fly larvae and target mosquitoes. The insect species are determined by whether the particular Bt produces a protein that can bind to a receptor Intestine of the larva, thus causing the insect larvae to die of hunger.
2. Biochemical pesticides are natural substances, such as plant extracts, fatty acids or pheromones, which control pests using a non-toxic mode of action for the pest. Conventional pesticides, on the other hand, are generally synthetic materials that directly kill or inactivate the pest, most frequently by attacking the nervous system. Biochemical pesticides, while non-toxic, can be lethal, such as insect-stifling clays, anti-hunger compounds, or vinegar that kills plants. Other biochemical pesticides include substances such as insect sex pheromones that disturb mating, insect repellent insect repellents, and various aromatic plant extracts that attract insect pests to traps. The EPA has established a special committee to evaluate the products and to determine if a substance meets the criteria to be classified as a biochemical pesticide.
Built-in Plant Protectors (PIP)
Pesticides are substances that plants produce from genetic material that has been added to the plant, such as corn and cotton. Scientists have taken the gene for the Bt pesticide protein, and the gene was introduced into the plant's own genetic material. The plant, instead of the bacterium Bt, manufactures the substance that destroys the pest. The protein and its genetic material, but not the plant itself, are regulated by the EPA.
The success of PIPs in large-scale commercial row-crop production can not be ignored. According to the USDA-ARS, tobacco leafworm (Heliothis virescens) and capsule worm (Helicoverpa zea) are two of the most destructive pests of cotton and other crops, with costs of control, production and yield loss up to $ 300 million per year in the United States alone. In the late 1980s the industry began to develop crops with a pest control function from Bacillus thuringiensis (Bt) genes, which produce proteins toxic to various insects, including the tobacco caterpillar and the capsule worm.
Cotton was one of the first crops to benefit from the biotechnology pest protection provided, and Bt cotton is now one of the most widely used transgenic crops. It is currently cultivated throughout the United States, China, India and Australia. More than 2 million acres of Bt cotton are grown in the United States alone. Other crops, including corn, potatoes, soybeans, and now also contain Bt genes.
The use of PIPs or genetically modified crops is generally considered to be based on planting and crop management decisions. For this reason, only the use of microbial and biochemical pesticides in effective pest control programs are addressed in this course.
Before a conventional pesticide can be marketed and used in the United States, the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) requires EPA to evaluate the proposed pesticide to ensure that its use does not represent "an excessive risk of harm to Human health and the environment. "This regulation implies an extensive review of health and safety information. To this end, the EPA may require more than 140 different studies on the toxicology of a chemical, crop residues and environmental effects.
The EPA also establishes tolerances (maximum pesticide residue limits) for the amount of pesticide that can legally remain in food.
Normally, biopesticides receive tolerance exemptions because they are biodegradable or microbial and the establishment of residue levels is not appropriate.
Biopesticides are regulated by the same laws and regulations as the chemical pesticides by Biopesticide contamination and the EPA Prevention Division. However, because biopesticides tend to pose fewer risks than conventional pesticides, EPA generally requires less data to register a biopesticide than the registration of a conventional pesticide. Consequently, the new biopesticides are registered in less than the average of 3 years that are needed for the registration of conventional pesticides. The time for biopesticide approval is 12 months for ornamental plants and turf (non-food crops) and 18 months for food crops, which is governed by the Pesticide Registration Improvement Act (PRIA).
The EPA has implemented a staged procedure for biochemical pesticide data needs that reduces the amount of testing, and saves money, time, and the number of animal testing. The EPA may waive certain data if the original chemistry of the product or substance is food grade. If the initial toxicity tests are negative at the maximum dose, no further testing is required, especially when the substance is well known. In addition, public literature is often used to support a biochemical compound. According to the EPA, most of the pheromone compounds have been exempted from the test through a process of deregulation
Microbial pesticides have slightly different EPA protocols. These products are predominantly bacteria, but they also include fungi and viruses, which can directly kill an insect pest or out of competition with a naturally occurring pest species. Each strain of these pesticides has been registered as a separate active ingredient.
EPA requires the following for microbial pesticides:
Chart of the product and keeping specimens in a recognized crop collection
Track pathogenicity rather than toxicity (for how long it takes for the microbe to be cleared from a test animal), and
More extensive tests that are not subject to chemical pesticides since these are organisms capable of reproducing in the field of life. For example, 30 days of study feeding is required to assess the pathogenicity of ladybugs, laceworms and bees.
Although the timeline is reduced, field trials of biopesticides to be registered for use in high value specialty crops such as fruits, vegetables, nursery plants and ornamental plants is disproportionately expensive for small biopesticide manufacturers. In addition, the return on investment for the agrochemical industry is limited compared to that of conventional pesticide development and use.