Biopesticides

Biopesticides are crop protection products which have been designed for repeated application, whose active ingredient is a micro-organism such as a bacterium, virus, fungus, microscopic nematode or microsporidium or part of a micro-organism.  These characteristics make them attractive components for organic farming practices.  At the end of 2001, there were approximately 195 registered biopesticide active ingredients and 780 products.  Biopesticides account for about 20% of all pesticide active ingredients registered in the USA.

Biopesticides fall into three major categories:

  1. Microbial pesticides such as Bacillus thuringiensis or Bt.  Each strain of Bt produces a different mix of proteins which can specifically kill one or a few related species of insect larvae.  While some Btís control moth larvae found on plants, other Btís are specific for fly or mosquito larvae.  The Bt produces a protein, which is ingested by the insect.  The protein binds to a gut receptor causing the insect larvae to starve to death.  About 60-90% of the global biopesticide market can be attributed to Bt.

  2. Plant-incorporated-protectants (PIPís) are pesticidal substances produced from genetic material which has been added to a plant (e.g. Bt Cotton).  The gene that codes for the Bt pesticidal protein can be introduced into the plantís genetic material allowing the plant to then produce the Bt toxin.

  3. Biochemical pesticides are naturally occurring substances that control pests by non-toxic mechanisms.  Conventional pesticides are synthetic materials that can directly kill insect pests.

General Qualities of Effective Biopesticides

The qualities of an effective biopesticide are similar to that of a chemical pesticide:  they must work with good efficacy against the pest for which they are labeled.  There has been considerable consumer and governmental pressure to minimize the use of chemical pesticides.  This can be seen by the desire of the consumer to purchase organic produce and by supermarkets demanding that growers utilize environmental sensitive crop production strategies.  The unique value for biopesticides is based on the three ďRísĒ:

Resistance management

Since biopesticides have multi-modes of action, there is less chance of developing resistance in a particular insect.   Biopesticides can be an excellent component of an integrated pest management (IPM) program.  An IPM program involves a grower applying two or three chemical pesticides and then using a completely different product to vary the mechanism of action.  Through government, supermarket and consumer pressure, IPM is becoming increasingly established as the future of crop protection.

Restricted entry intervals

Restricted entry intervals (REIís) determine the timing of application relative to a number of factors.  The majority of biopesticides have low REIís, mostly around 0-4 hours with no pre-harvest interval.  After a biopesticide is applied, a farmer can go into the field and harvest immediately.

Residues

Residues are a regulatory issue with pesticides.  The Environmental Protection Agency (EPA) has jurisdiction over their proper application.  The Office of Pesticide Programs of the EPA has established a Biopesticide and Pollution Prevention Division (BPPD).  This group helps to coordinate the registration of biopesticide products (www.epa.gov/pesticides/biopesticides). Since biopesticides tend to pose fewer risks compared to conventional chemical pesticides, the EPA generally requires less data to achieve new product registrations (< 1 year).  Conventional chemical pesticides can take up to three years for regulatory approval.

The Ďrisk cupí system places a limit on the total, cumulative, potential exposure to a pesticide across all of its applications. This system has forced companies to make the choice between registering specific agrochemicals solely for use on major crops, or to limit their use on major crops to enable their use on a larger number of less widely grown crops. Unsurprisingly, agrochemical companies have focused their registration of new pesticides on the high acreage field crops. Many have also taken the decision not to support older products through re-registration of high value niche crops. The USDA Inter-Regional Project No 4 (IR-4) program is helping to support the registration of crop protection products on minor crops by carrying out some of the trials required for completion of a registration dossier, with the support of the relevant company. This government initiative has helped to limit some of the crop protection product availability problems faced by minor crop growers but has not entirely prevented a shortfall in crop protection product availability in some minor crop sectors.

The cost of registration of a biopesticide product is usually an order of magnitude less than for a chemical pesticide product. In the US, the cost of registration of a biopesticide can usually be measured in hundreds of thousands of dollars.  In contrast, registration of a chemical pesticide costs millions of dollars. This reflects the regulatorís preference for biopesticides, especially Bt products. Because of high chemical registration costs, many high value crop and niche markets are now being left without effective chemical crop protection solutions, leaving Bt as the economical choice for many producers. These markets represent a growth opportunity for InsectiGenô.

Additional qualities of biopesticides

Some other feature of biopesticides include:  narrow target range, specific mode of action, slow-acting, safer than chemicals, limited field persistence, high unit cost of biopesticide production and they suppress but do not eliminate pests.