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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #154326
Title: EFFECTS OF MESOCRICONEMA XENOPLAX ON VITIS VINIFER AND ASSOCIATED MYCORRHIZAL FUNGI.

Author
item Pinkerton, John
item Schreiner, Roger - Paul
item IVORS, K.L. - OSU
item VASCONCELOS, M.C. - OSU

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2004
Publication Date: 9/1/2004
Citation: J.N.PINKERTON, R.P. SCHREINER, K.L.IVORS, M.C. VASCONCELOS. EFFECTS OF MESOCRICONEMA XENOPLAX ON VITIS VINIFERA AND ASSOCIATED MYCORRIHIZAL. JOURNAL OF NEMATOLOGY. 2004. 36(3):193-201.

Interpretive Summary: Surveys of vineyards found that the ring nematode, Mesocriconema xenoplax, was present in 85% of vineyards in western Oregon. However, M. xenoplax was not associated with depressed fruit yields in established vineyards. Many vineyards are being replanted on sites infested with this nematode. The current research was conducted to determine the effects of the ring nematode on the establishment of new vines. In 1997, field plots were infested with 0.03, 0.6, and 3.0 M. xenoplax g-1 soil. These population densities correspond to the detection threshold, those typical of Oregon vineyards, and the highest density found in the survey, respectively. Plots were planted with self-rooted Chardonnay and Pinot Noir vines. After four growing seasons, pruning weights, fine root weights and fruit yield of vines planted in infested soil were reduced by 58%, 75%, and 33%, respectively, relative to control vines (planted in non-infested soil). These data suggest that the ring nematode may be an important constraint to establishing vineyards. The effect on M. xenoplax on symbiotic mycorrhizial fungi also was investigated. The nematode did not reduce fine root colonization by arbuscular mycorrhizal fungi. However, the frequency of fine roots containing arbuscules (the site of nutrient transfer between plant and fungus) was significantly depressed in plants infested with M. xenoplax as compared to controls. Competition for photosynthate within the root system is proposed as the mechanism by which nematodes suppressed arbuscule frequency.

Technical Abstract: Surveys of vineyards had previously reported that Mesocriconema xenoplax was present in 85% of vineyards in western Oregon, but yields were not depressed in established vines. Microplot studies were initiated in 1997 in a Willamette Valley vineyard to determine the impact of M. xenoplax on vine establishment. Plots were infested with 0.03, 0.6, and 3.0 M. xenoplax g-1 soil and planted with self-rooted Chardonnay and Pinot Noir vines. In November 2000, four growing seasons after planting, pruning weights, fine root weights and fruit yield of vines planted in infested soil were reduced by 58%, 75%, and 33%, respectively, relative to control vines (planted in non-infested soil). In 1998 with ca 2000 degree-day base 9º C accumulation, population densities increased 32' fold and 44' fold on one-year-old Chardonnay and Pinot Noir vines, respectively. Nematode population dynamics and pruning data suggest that the carrying capacity of vines in microplots was 5-8 M. xenoplax g-1 soil. In November 2000, > 80% of the fine root length was colonized by arbuscular mycorrhizal fungi in all treatments. The frequency of fine roots containing arbuscules (the site of nutrient transfer between plant and fungus), however, was significantly depressed in plants infested initially with M. xenoplax as compared to controls. Competition for photosynthate within the root system is proposed as the mechanism by which nematodes suppressed arbuscule frequency.