University of Georgia College of Agricultural & Environmental Sciences
Cooperative Extension Service

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Nematode Control in the Home Vegetable Garden

Johnny Dan Gay, Extension Plant Pathologist

Nematodes are small, eel-like worms that live in the soil and feed on the roots of plants. In the process of feeding they cause the roots to become knotted and galled. Not only do they impair the root system so that water and nutrients cannot be taken up, they also cause injury which may enhance soil-borne disease development. Nematode damaged plants become stunted, turn yellow and wilt in hot weather. The best time to determine if you have a nematode problem is in the summer and fall, when nematodes are most numerous. Roots may be dug from the soil and examined for the presence of root-knot galls. The numbers and kinds of nematodes in the soil may be determined by taking a soil sample to the county Extension office for them to send to the Nematode Assay Laboratory in Athens.

While it is practically impossible to rid the soil completely of destructive nematodes, you may reduce them to nondamaging numbers by the methods listed in this publication.

Cultural Practices to Reduce Root-Knot Nematodes

Crop Destruction: As soon as the last harvest is made, nematode-susceptible crops should be pulled up and removed from the garden site. Numerous nematodes and eggs trapped in the root system will be eliminated from the area. This practice will reduce the root-knot nematode population. However, it will not eliminate future damage on susceptible crops.

Fallowing: Nematodes require a film of water around them at all times. Eliminating the film of water kills the nematodes. Repeated disking in the hot, dry summer months will bring nematodes to the surface to be killed by the drying of the sun.

Rotation: Rotation is invaluable in reducing root-knot nematode damage, but space usually limits the ability to rotate garden sites. Planting nematode infested areas to French Marigolds (Tagetes patula) will control nematodes provided no other root systems are present. Marigolds should be planted no more than seven inches apart. The garden can be divided, with half planted to marigolds and half to vegetables. The plantings should be reversed the next year. Other French marigold varieties, Tangerine, Petite Harmony, or Petite Gold, may be used.

Clean Transplants: Nematode-free areas can be reinfested by bringing in infected transplants. Either grow your own in sterilized soil or buy plants from a reputable dealer who grows in a sterilized medium.

Woods dirt is good for growing your own transplants. It can be sterilized by spreading the soil in a pan and placing in the oven at 180 degrees to 200 degrees F for 35 to 40 minutes.

Resistant Varieties: Plant resistant varieties when possible. Good resistance is available in many tomato varieties and some other vegetable crops. Tomato varieties with the letters VFN mean the variety is resistant or tolerant to Verticillium wilt, Fusarium wilt and nematodes. Using resistant varieties is the easiest, least expensive, and most effective means of nematode control.

Unfortunately, varieties resistant to root-knot are available only in certain crops.

Organic Control

Clandasan 618 produced by Iogene Biotechnology advertisized to reduce nematodes. Clandosan is an organic nematicide made of chitin (extracted from shellfish wastes), soybean meal and urea. The material works by increasing the population of soil microorganisms that can feed on chitin. Chitin is one of the primary components in the body wall of nematicides. The feeding activities of the chitin-loving microorganisms have been shown to reduce the number of nematodes for the cropping sequences. However, control is sporadic and requires large quantities of an expensive product. Clandosan should be incorporated into the soil about 2 weeks before planting. We have not achieved control with this material in Georgia.

ATTENTION!

Pesticide Precautions

1. Observe all directions, restrictions and precautions on pesticide labels. It is dangerous, wasteful and illegal to do otherwise.
2. Store all pesticides in original containers with labels intact and behind locked doors. KEEP PESTICIDES OUT OF THE REACH OF CHILDREN.
3. Use pesticides at correct label dosage and intervals to avoid illegal residues or injury to plants and animals.
4. Apply pesticides carefully to avoid drift or contamination of non-target areas.
5. Surplus pesticides and containers should be disposed of in accordance with label instructions so that contamination of water and other hazards will not result.
6. Follow directions on the pesticide label regarding restrictions as required by State or Federal Laws and Regulations.
7. Avoid any action that may threaten an Endangered Species or its habitat. Your County Extension Agent can inform you of Endangered Species in your area, help you identify them, and through the Fish and Wildlife Service identify actions that may threaten Endangered Species or their habitat.

Trade and brand names are used only for information. The Cooperative Extension Service, University of Georgia College of Agricultural and Environmental Sciences does not guarantee or warrant published standards of any product mentioned; neither does the use of a trade or brand name imply approval of any product to the exclusion of others which may also be suitable.

The University of Georgia and Ft. Valley State College, the U.S. Department of Agriculture and counties of the state cooperating. The Cooperative Extension Service offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, sex or disability.

An Equal Opportunity Employer/Affirmative Action Organization Committed to a Diverse Work Force

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, The University of Georgia College of Agricultural and Environmental Sciences and the U.S. Department of Agriculture cooperating.

Gale A. Buchanan, Dean and Director

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