History of Biopesticides

Biologicals are used to control pests, pathogens, and weeds by a variety of means. Microbial biocontrols may include a pathogen or parasite that infects the target. Alternatively, they might act as competitors or inducers of plant host resistance. Biochemical biocontrols can also act through a variety of mechanisms. Some act by inhibiting the growth, feeding, development or reproduction of a pest or pathogen. Still other biocontrols may be used to form a barrier on the host, so as to act as a feeding or infection inhibitor.

Plant extracts were likely the earliest agricultural biocontrols, as history records that nicotine was used to control plum beetles as early as the 17th century. Experiments involving biological controls for insect pests in agriculture date back as far as 1835, when Agostine Bassi demonstrated that w hite-muscadine fungus (Beauveria bassiana) could be used to cause an infectious disease in silkworm. Experiments with mineral oils as plant protectants were also reported in the 19th century. During the rapid institutional expansion of agricultural research during the early 20th century, an ever-growing number of studies and proposal for biocontrols were developed.

The first, and still most, widely used biocontrols included spores of the bacteria Bacillus thuringiensis (Bt). I n 1901, Bt was isolated from a diseased silkworm by Japanese biologist Shigetane Ishiwata. Ernst Berliner in Thuringen, Germany, then rediscovered it ten years later in a diseased caterpillar of flour moth. The Bt pathogen was classified in 1911 as type species Bacillus thuringiensis and remains the most widely used biocontrols to this day. In the early 1920 s, the French began to use Bt as a biological insecticide. The first commercially available Bt product, Sporeine, appeared in France in 1938. In the US in the 1950 s, widespread use of biocontrols began to take hold as a host of research on Bt efficacy was published.

In the latter half of the 20th century, research and development continued at a low level because of the widespread adoption of cheaper but more toxic synthetic chemical insecticides. During this time, new products were developed and applied; especially in niche markets where petroleum based chemicals were not registered, not effective, or not economical. For example, in 1956, the Pacific Yeast Product Company developed an industrial process known as submerged fermentation, which allowed production of Bt on a large scale. In 1973, Heliothis NPV was granted exemption from tolerance and the first viral insecticide, Elcar received a label in 1975. In 1977, Bacillus thuringiensis var. israelensis (toxic to flies) was discovered, and in 1983 the strain tenebrion is (toxic to beetles) was found. In 1979, the U.S. EPA registered the first insect pheromone for use in mass trapping of Japanese beetles. In the 1990s, researchers began testing kaolin clay as an insect repellent in organic fruit orchards. It was made commercially available, particularly for use in organic systems, in 1999.

Biological development for the control of plant diseases has undergone a similar transformation. During the early 20th century, studies of soil microbiology and ecology had led to the identification of many different microorganisms that act as antagonists or hyperparasites of pathogens and insect pests. A number of these were shown to be useful in field-scale inoculations, but few were developed commercially because of the rapid adoption of chemical pesticides during that time period. Commercial success stories from the 1980s and 1990s include products containingAgrobacterium radiobacter for the prevention of crown gall on woody crops and Pseudomonas fluorescen s for the prevention of fireblight in orchards where the streptomycin had been overused and resistant pathogen populations were abundant. In the greenhouse and potting mix industry, products containing a variety of microbes that suppressed soilborne pathogens were introduced into the market.

As the costs of overusing such synthetic chemicals became apparent, there was resurgence in academic and industrial research related to biocontrols development. And with the rapid expansion of organic agriculture during the past decade, adoption rates have rapidly increased. Because of this, development of new and useful biocontrols has continued to increase rapidly since the mid-1990 s. In fact, more than 100 biocontrols active ingredients have been registered with the U.S. EPA Biologicals division since 1995. Many of these have been introduced Biologicals division since 1995. Many of these have been introduced commercially in a variety of products. Many of the active ingredients currently approved for use in the U.S.A. can be found in publicly available databases.