Pacific Northwest 1998 An Online Guide to Plant Disease Control

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OSU Extension Office
 
Grape -- Nematode (Ring)
 
Cause: Mesocriconema xenoplax, an ectoparasite (see Nematodes) that gets its common name from the cuticular ring ornamentation around its body. The nematode moves slowly as it browses along the root and may feed at one site up to 7 days. Ring nematode was found in 85% of Oregon vineyards surveyed but in only 5% of Washington vineyards.
Symptoms: At high population densities, this nematode can cause extensive root pruning which stresses the plant and reduces yields.
Sampling: Best sampling time west of the Cascades is February or March when populations are high and moist soil is easy to sample. In eastern Washington, the best time to sample is at the end of the growing season when populations are highest. Take samples 1 ft from the vine and in the vine row. Remove the top 2 to 3 inches of soil and sample 1 ft deep with a soil tube 1 inch in diameter. Take 10 to 20 subsamples in a given area and combine into one sample. In Washington, 300 nematodes per 250 cc of soil reduced 'Concord' grape yields. In western Oregon, ring nematodes are rarely associated with significant yield reduction in established vineyards. However, this nematode can affect the establishment and yield of young vines.

It is important to specify that you are interested in ring nematode numbers when sending soil samples to the OSU Nematode Testing Service. Ring nematodes are larger and more sluggish and are not easily detected with Baerman funnels, so special extraction procedures must be used.

Cultural control:

  1. Use clean root stock.
Chemical control:

  1. Preplant fumigation.
    1. Telone II up to 55 gal/A in mineral soils. Soil conditions where grapes are grown are often not conducive for optimum performance of this fumigant. Check label for proper ground preparation before application. 5-day reentry. Restricted-use pesticide.
  2. Enzone can be used through low volume irrigation systems. Use 5 to 30 gal/A/treatment for established vineyards or 20 to 60 gal/A/treatment before planting. Soil temperature must be above 58°F at 6 inches and plants must be established for at least 1 year before treatment. Several applications to an existing vineyard are recommended on the label. Do not apply within 2 weeks of harvest. Oregon and Washington only. 4-day reentry.
Biological control: DiTera ES (Myrothecium verrucaria strain AARC-0255) is registered for many nematodes on grapes. Field and greenhouse tests by the USDA found the product was ineffective for suppressing ring nematode populations. 4-hr reentry.
Content edited by: John Pinkerton and Jay W. Pscheidt on January 1, 2009
 
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