Purpose of Nematode Management: To keep nematode population densities at a low level during the early growing season to allow cotton plants to establish healthy root systems. It is not possible to completely eliminate plant-parasitic nematodes.
Steps for Developing a Nematode Management Program:
- Sample field(s) to determine if nematodes are present; if so, establish population density levels. If NO species are detected, the strategy is to make sure none are introduced.
- If nematodes are present, the strategy is to keep them from spreading to non-infested fields and to reduce population densities.
- Effective management practices require knowing which field(s) is/are infested, genera present, and population densities.
- Lance nematodes should be identified by specific species.
- Develop a Nematode Management Program well in advance of planting.
(For more information, see Nematode Soil Sampling).
- Review analysis of soil samples taken last fall to identify nematode species, their locations, and their densities.
- Review nematode control options -- cultural and chemical practices -- that are available/practical in your situation.
- Design and follow a strategy that suits your special situation. Consider factors such as history of cropping patterns, soil types, single/multiple nematode species present, and weather anticipated.
Types of Nematode Management Practices:
- Use of tolerant varieties of cotton. Many early resistant cotton varieties were developed primarily to control the root-knot nematode/Fusarium wilt complex. The Acala variety has shown good resistance in western areas. Today most commercial varieties have some tolerance to root-knot. Very few varieties of cotton show significant tolerance to other major cotton nematodes.
- Cultural practices:
- Tillage. Exposure of the root systems will reduce nematode populations by exposing them to drying and temperature extremes. Sub-soiling can be used in some areas to aid in deeper plant root penetration.
- Water Management. Irrigation reduces crop moisture stress in fields with nematode populations.
- Clean Equipment. Wash all tractor equipment to remove soil and root debris before moving from infested to non-infested fields
- Rotation. Rotation of a non-host crop with cotton for one or more years reduces nematode populations. Check with your state specialist to for the best rotations in your area.
- Chemical Controls: The goal is to protect plants early in the growing season allowing them to produce deep, healthy root systems. CONTROL IS TEMPORARY. The availability and conditions for using these materials vary from state to state. Specific recommendations and guidelines are available from local extension agents and state specialists.
- Fumigants. These are non-selective materials that vaporize when applied in the soil. As gases, they move up through air spaces in the soil, killing nematodes and other microorganisms. After applying most fumigants, a waiting period is required before planting.
- Non-fumigants. These are available in liquid or granular forms. They are applied either in a band or in the seed furrow at planting. These materials move down through the soil killing nematodes directly, or by interfering with feeding and reproduction.
- Seed treatments. These are products are applied to the seed coat. They may kill nematodes directly or interfere with feeding and reproduction. These have increased in popularity due to ease of application.
- Foliar applications. These are post plant applications that have efficacy on nematodes and insects.
- Biologicals. These are living organism that interfere with growth and reproduction of some species of nematodes. Some are species specific and others are broad spectrum.