Nematodes

Nematodes are tiny, worm-like, multicellular animals that are adapted to living in water. The number of nematode species is estimated to be half a million.

As an important part of the soil fauna, nematodes live in a maze of interconnected passages called pores, which are produced by soil action. They move in a film of water attached to soil particles.

Most of the plant-parasitic nematodes are root feeders, which are found associated with most plants. Some nematodes are endoparasitic, living and feeding in the tissues of roots, tubers, buds, seeds, etc. Others are ectoparasitic, feeding externally through the plant wall.

An endoparasitic nematode can kill a plant or reduce its productivity. Endoparasitic root feeders include such economically important pests as root-knot nematodes (Meloidogyne species), kidney-shaped nematodes (Rotylenchulus species), cyst nematodes (Heterodera species), and root-rot nematodes (Pratylenchus species).

Direct feeding by nematodes can severely reduce the nutrient and water intake of plants. When nematodes attack the roots of seedlings immediately after seed germination, they have the greatest impact on crop productivity.

Nematode feeding also creates open wounds that provide entry for a variety of plant pathogenic fungi and bacteria. These microbial infections often cause more severe economic damage than the direct effects of nematode feeding.

Current nematode control is primarily focused on preventing nematodes from attacking plants. Once a plant is infested, it is virtually impossible to kill the nematode without damaging the plant. It would therefore be advantageous to provide nematode control compounds and methods of treating plants to prevent or reduce nematode damage.