Fungi-based bioinsecticides

Fungi that cause disease in some 200 different insects are gaining prominence as bioinsecticides. One of the earliest to be discovered in the 1880s is Beauveria bassiana (Bb), a fungus found worldwide in soils and plants. Another half a dozen fungi are also known to have characteristics valuable for insect control. In China, over two million hectares are sprayed with Bb annually to control forestry pests. Since 1993, six new fungal bioinsecticides have become available in North America and Europe.

Inexpensive fermentation technology is used to mass produce fungi. Spores are harvested and packaged so they can be applied to insect-ridden fields. When the spores are applied, they use enzymes to break through the outer surface of the insects’ bodies. Once inside, they begin to grow and eventually cause death.

Bioinsecticides based on Bb have many advantages. The fungus does not grow in warm-blooded organisms (such as people), nor does it survive long in water reservoirs or rivers. However, its spores can withstand long periods of dryness and other harsh environmental conditions. Studies to date have shown that the fungus also does not hurt plants and becomes inactivated by the sun’s ultraviolet rays in one to eight weeks.

Fungal agents are viewed by some researchers as having the best potential for long-term insect control. This is because these bioinsecticides attack in a variety of ways at once, making it very difficult for insects to develop resistance.