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Plant Pathology Infobytes

December 9, 1998

Reduce Garden Nematode Problems with Clandosan

Root-knot and other plant-feeding nematodes can be the source of frustration for home vegetable gardeners. These pesky creatures are too small to be seen with the unaided eye, but what they lack in size they make up in numbers. It's not uncommon for several thousand of these tiny worms to attack the root system of a susceptible garden plant.

For those nematode "hot spot" areas of your garden try planting a vegetable variety which has resistance to root-knot nematodes. "Better Boy" and "Celebrity" varieties of tomatoes are a good choice and are resistant not only to nematodes but Fusarium wilt as well. Check the Garden Tabloid (available at your county Extension office) for a listing of other types of root-knot resistant vegetable varieties.

What about nematode control options other than the use of resistant varieties? Gardeners who are interested in trying another approach, might want to consider Clandosan 618 Chitin Nematicide. Clandosan 618 is a product made from ground crab and shrimp shells recovered as by-products of sea food processing. The ground shells, along with agricultural grade urea, are formed into granular pellets and contain no artificial or synthetic substances, or any product derived from petrochemical sources.

How does Clandosan control nematodes? Prior to planting the garden, the product is tilled into nematode-infested soils to a depth of about six inches. The Clandosan then acts as a growth stimulus for the multiplication of normal soil microorganisms, such as actinomycetes, bacteria, and fungi.

After a week or so of feeding on the Clandosan, the "good guy" microorganisms reach high population levels in the soil and need a new sources of food. The new food supply turns out to be root-knot and other damaging types of nematodes, and within two to four weeks after application, Clandosan should have reduced the root-knot nematode population to a non-damaging levels.

However, garden tests conducted in Clay County in cooperation with the County Agent, indicate four weeks may not be sufficient to reduce nematode populations in areas where root-knot populations have reached exceptionally high levels. Therefore, it would be a good idea to collect soil samples for analysis from treated areas before planting nematode susceptible garden plants. For directions on the procedure for collecting nematode samples, contact your County Extension Office.

For more information about this Clandosan 618, check with your garden supply dealer. If this product isn't available, ask about other chitin-containing nematicides, which may be available.

Infobytes newsletter was written by the late Dr. Frank Killebrew, Extension Specialist.