Nematodes

Nematodes are the most numerous multicellular animals on earth. There are nearly 20,000 described species in the phylum Nemata, and a handful of soil typically contains thousands of these microsocopic worms. Most nematodes feed on bacteria, fungi, and other soil organisms. Others are parasitic, obtaining their food from animals (such as the dog heartworm), humans (such as the pinworm), and plants.

Plant-parasitic nematodes generally attack the root system. Nematode feeding reduces the flow of water and nutrients into the plant, and thus reduces the yield of agricultural crops. In addition, nematode infestations weaken plants, making them more susceptible to other stress factors such as heat, water, and nutritional deficiencies, and to other disease-causing organisms. Agricultural cultivation encourages an increase in parasitic nematodes that feed on the crops being grown. Occasionally, new kinds of plant parasitic nematodes may be introduced into a field by contaminated plant parts, soil on farm equipment, and irrigation water.

There are many different types of plant-parasitic nematodes, but only about 10 different genera cause most of the problems in agriculture and horticulture. Each type of nematode generally prefers to attack specific plants. For example, the root knot nematode (various species of the genus Meloidogyne) attacks peanuts, tomatoes, tobacco, and corn.

These plant-parasitic nematodes are the largest unmet problem in agriculture today. Approximately 28% of US crop acreage planted with field crops, vegetables, potato, fruits, and nuts is infested with nematodes at economically damaging levels. The levels of infestations are even higher in the southern hemisphere, and among certain specialty crops. For example, it is estimated that 40% of US strawberry acreage is infested with nematodes (and 70% of the acreage receives chemical nematicide treatment). 900,000 acres of peanuts in the US are infested by the root knot nematode, causing $81 million in losses annually.

In the US alone, nematode damage in major crops is estimated to reduce crop yields be more than $5 billion per year. The Society of Nematology and other organizations estimate worldwide crop losses due to nematodes at $100 billion annually.

Society places a high value on preserving the environment and on the safety of the food and water supply. The increasing demand for very low or undetectable pesticide residues on food plants and in groundwater supplies has caused a sharp decline in the types of nematicides that can be applied to soil. The EPA has removed many of these compounds from the market and has continued to increase restrictions on the use of the few that remain. Following the Montreal Protocol the U.S. will phase out the agricultural use of methyl bromide by 2005. This will be a major loss to growers’ arsenal of nematode control products. The cost of producing new products is high enough (in some cases as much as $50 million for toxicity and environmental impact testing) that U.S. chemical manufacturers have discontinued research and development on new nematicidal compounds. Many agricultural systems, such as golf courses, home gardens, commercial greenhouses and horticultural crops, have few nematode control products available, due to safety and environmental concerns. The demand from these industries for effective alternative methods of plant-parasitic nematode control is increasing and few alternatives are present to meet these demands. There is clearly a need for development and commercialization of environmentally safe, cost-effective and reliable nematode control products to fill the niches that will be vacated by current nematicides and to meet the demand of growers, who will be left without effective products available. Pasteuria Bioscience has the solution: a group of bacterial parasites of nematodes, Pasteuria sp. They have been recognized for decades as promising control agents for plant-parasitic nematodes but commercial development was thwarted by a lack of cost-effective production methods. The breakthrough technology developed by Pasteuria Bioscience now makes this production possible and paves the way for a new class of nematode control agents.