Location: Horticultural Crops ResearchTitle: Spatial distribution of plant-parasitic nematodes in semi-arid Vitis vinifera vineyards in Washington
Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2014
Publication Date: 12/1/2014
Citation: Howland, A.D., Schreiner, R.P., Zasada, I.A. 2014. Spatial distribution of plant-parasitic nematodes in semi-arid Vitis vinifera vineyards in Washington. Journal of Nematology. 46:321-330.
Interpretive Summary: Plant-parasitic nematodes are microscopic roundworms that have been shown to cause significant yield loss in grapevines worldwide. Washington has growing wine grape industry and is the second largest grape producing region in the United States. Despite the fact that plant-parasitic nematodes are important parasites of grapevines, no information is available on the distribution of these organisms in Washington vineyards. This research was conducted to determine the spatial distribution of plant-parasitic nematodes in vineyards. Soil samples were collected from two vineyard and sampling was designed to characterize the distribution of nematode vertically as well as horizontally within a vineyard. Root-knot and ring nematodes were found to be aggregated under drip irrigation emitters and numbers of these nematodes were related to soil water content and the presence of roots. The root lesion nematode was not associated with grape roots or soil water content and was found primarily in the alleyways of vineyards. Dagger and pin nematodes were more random in distribution with no consistent trends detected. These results are significant because they are the first to demonstrate where plant-parasitic nematodes are found in semi-arid Washington vineyards. This research will be used by vineyard managers to better manage plant-parasitic nematodes in commercial vineyards.
Technical Abstract: The most commonly encountered plant-parasitic nematodes in eastern Washington Vitis vinifera vineyards are Meloidogyne hapla, Mesocriconema xenoplax, Pratylenchus spp., Xiphinema americanum, and Paratylenchus sp.; however, little is known about their distribution in the soil profile. The vertical and horizontal spatial distribution of plant-parasitic nematodes was determined in two Washington V. vinifera vineyards. Others variables measured in these vineyards included soil moisture content, fine root biomass, and root colonization by arbuscular mycorhizal fungi (AMF). Meloidogyne hapla and M. xenoplax were aggregated under irrigation emitters within the vine row and decreased with soil depth. Conversely, Pratylenchus spp. populations were primarily concentrated in vineyard alleyways and decreased with depth. Paratylenchus sp. and X. americanum were randomly distributed within the vineyards. Soil water content played a dominant role in the distribution of fine roots and plant-parasitic nematodes in Washington semi-arid vineyards. Colonization of fine roots by AMF decreased directly under irrigation emitters; in addition, galled roots had lower levels of mycorrhizal colonization compared to healthy roots. These findings will help facilitate sampling of and management decisions for plant-parasitic nematodes in Washington semi-arid vineyards.