New varieties offer options to growers, gardeners - Root-knot nematodes are
extreme parasites. These microscopic, omnipresent worms cause major damage
to horticultural and field crops in sub-tropical regions, resulting in
significant financial losses to growers and gardeners.

Until recently, fumigation of the soil with methyl bromide before planting
was the primary method for controlling root-knot nematodes in valuable
vegetable crops. Methyl bromide (MeBr) is an odorless, colorless gas that
has been widely used as a plant pesticide. Since the discovery that the
substance has severe negative effects on the environment?it depletes the
stratospheric ozone layer?the use of methyl bromide has been phased out in
the U.S.

To combat parasites like root-knot nematodes without the use of chemical
pesticides, scientists are focusing more research on developing new,
parasite-resistant varieties of vegetables. Dr. Judy Thies, a research plant
pathologist at the U.S. Department of Agriculture's Agricultural Research
Service, was part of a team of scientists who developed the Charleston Belle
variety of bell pepper, the first nematode-resistant bell pepper.

In a study published in the February issue of the American Society for
Horticultural Science's journal HortScience, Dr. Thies and her colleagues
tested the stability of two types of bell peppers, Charleston Belle and
Carolina Wonder. Thies explained, "These two types of pepper cultivars are
the only nematode-resistant varieties available to commercial growers and
home gardeners. Since a large percentage of bell pepper production in the
U.S. occurs in the Southeastern U.S., and in particular Florida, we tested
the peppers for resistance to nematodes in sub-tropical climates to
determine if the cultivars were stable when grown in Florida under high soil
temperatures. It is important to know whether the peppers' resistance to
parasites breaks down when peppers are grown in hot climates."

Good news for growers and gardeners: study results showed that
nematode-resistant varieties such as Charleston Belle and Carolina Wonder
are viable alternatives to methyl bromide for managing southern root-knot
nematode in bell pepper in sub-tropical environments. To increase the
availability of parasite-resistant vegetables, commercial seed companies are
currently developing nematode-resistant hybrid bell peppers using both
Charleston Belle and Carolina Wonder.

The complete study and abstract are available on the ASHS HortScience
electronic journal web site:
[hortsci.ashspublications.org]

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