There are several classes of biopesticides: microbial pesticides consist of a microorganism such as a bacterium, fungus, virus, or protozoan. The most widely known microbial pesticide is various strains Bacillus thuringiensis or as it is better known as Bt. This soil bacterium produces toxins that kill a variety of pests. Different strains produce different proteins that kill different species. The Bts control moth larvae, fly and mosquito larvae, and some of the rootworms or beetle larvae. I think that it is somewhat ironic that Bt applied as a powder or liquid is legal to use under organic standards but the gene that produces the protein can?t be placed into plants to provide the same effective insect control.
Another category is the plant-incorporated-protectants that plants produce from genetic material that has been added to the plant. This would include the genetically modified organisms that produce proteins to allow plants to tolerate certain herbicides. This would include glyphosate or Roundup resistance. At the present time there are several of these being used in our major crops and several more that are being developed. There are also many other plants that include various proteins for insect control. In Missouri, about 99 percent of all of our cotton, and soybeans have either the herbicide resistance trait, insecticide resistance, or both.
The third class of biopesticides is referred to as the biochemical pesticides. These include insect sex pheromones; and scented plant extracts that serve as attractants. The insect sex pheromones can interfere with mating.
According to the EPA definition, a biopesticides must have a non-toxic mode of action such as suffocation, desiccation, starvation, or mating disruption. One of the most common materials that meet these criteria is a product called Safer Insecticidal soap. This material is made from naturally occurring plant oils and animal fats. As it penetrates the shells of soft bodied insects, it causes dehydration and death within hours. It can be used outdoors or indoors to control aphids, mealybugs, spider mites, and whiteflies. It does not kill beneficial insects such as ladybugs or praying mantises.
On December 14, an on-line article appeared in the Delta Farm Press written by Harry Cline, entitled, ?Biopesticides beyond organics.? This article can be found at http://deltafarmpress.com/news/biopestic.... The gist of the article is that in the past, the major market for biopesticides was for organic production. Now biopesticides account for about $1 billion compared with $35 billion in the worldwide pesticide market. Now, biopesticides are used in conventional agriculture production.
Marrone Bio Innovations which is headed by Pam Marrone, is one of the leaders in biopesticides development and marketing. One reason that biopesticides are catching on is that it only takes 12-18 months to get them through the registration process. One of the criteria that the EPA uses in registering additional pesticides is the issue of maximum residue levels. This is not a problem with the biopesticides. It generally takes about three years to register a conventional pesticide which is much more expensive than the process for biopesticides.
In general, conventional pesticides may affect non-target organisms. Either by direct contact or by drift. The biopesticides generally do not affect these organisms since they are effective in very small quantities and decompose very rapidly. They also work well in integrated pest management programs even when used with conventional pesticides. One of the advantages of the biopesticides is that it often has no pre-harvest interval after applying. Also, workers can re-enter the field very quickly after application.
Since biopesticides require less data and are registered in less time, the EPA still requires that registrants submit a variety of data about the composition, degradation, and toxicity.
Many of the major pesticide manufacturers are partnering with small startup companies so that they can provide a more environmentally safe pesticide. The BASF company has gone into partnership with Agri Quest to distribute a biofungicide, Serenade. Serenade contains a unique, patented strain of Bacillus subtilis (strain QST 713) which provides over 30 different proteins that work together to destroy disease pathogens and provide superior antimicrobial activity. It protects vegetables, fruit, and nut and vine crops against diseases such as Fire Blight, Botrytis, Sour Rot, Rust, Sclerotinia, Powdery Mildew, Bacterial Spot and White Mold.
Everyone who has traveled in the South is familiar with Kudzu. This has been a very large problem and very costly to control. However, there is hope. The fungal plant pathogen, Myrothecium verrucaria, is being developed as a bioherbicide of kudzu. This pathogen kills young kudzu plants and produces very rapid death, even on mature, well-established kudzu stands. Dr. Doug Boyette, at the Southern Weed Science Research Unit at Stoneville, Mississippi led the research effort to develop this bioherbicide.
University of Missouri Extension programs are open to all.
Dr. Michael R. Milam is an agronomy
specialist and county program director with
University of Missouri
Extension in Dunklin County.