Nematodes are microscopic, thread-like, non-segmented worms that inhibit the soil and feed on plant roots. They can be parasites in both plants and animals. Plant parasitic nematodes are small (barely more than a millimeter long) and translucent, and therefore, often invisible to the naked eye. Approximately 4,000 known plant parasitic nematode species exist.
All plant parasitic nematodes are obligate parasites and feed through a stylet. An obligate parasite is an organism that must feed on living plants to complete its life cycle. Some have broad host ranges, while others only infect a few host species.
There are three categories of nematodes that are classified by how they feed on roots:
- Endoparasitic – completely enters the host to feed from within
- Semi-endoparasitic – partially enters the root to feed, but also feeds from the outside
- Ectoparasitic – feeds only from the outside
Nematodes can be divided into two sub groups – Soybean Cyst Nematode (SCN) and non-cyst forming nematodes such as root-knot, reniform and lance nematodes.
Soybean nematodes can arise in any soil environment, but damage is often more apparent in lighter, sandier soils. Nematodes can enter fields through infested plant material, contaminated farm equipment, irrigation and run-off water, and dust storms. Once nematodes are established, they are hidden from sight in the soil, attacking root systems. Certain types of nematode species, specifically reniform nematodes, can be difficult to diagnose. By the time growers realize the problem, nematodes already may be well-established throughout the field.
Most of the nematodes that attack rotational crops, such as cotton and corn, also can cause significant injury to soybeans. Because cotton, corn and soybeans are all host crops to several of the same nematode species, growers who have battled nematode damage in their cotton fields can expect to see yield loss due to nematodes in their corn and soybean crops. A crop rotation of cotton, corn and soybeans is not effective method of inhibiting some nematode populations, so growers must implement a treatment program that helps ensure their soybean fields are protected from day one. With few rotational options and limited resistant soybean germplasm, management of these nematodes requires an effective nematicide.
Avicta 500FS is a Restricted Use Pesticide.
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