Vineyard soil texture and pH effects on Meloidogyne hapla and Mesocriconema xenoplax

Authors: East, Katherine; Zasada, Inga; Lee, Jungmin; Schreiner, Roger; Rippner, Devin

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/9/2023
Publication Date: 12/15/2023
Citation: East, K.E., Zasada, I.A., Lee, J., Schreiner, R.P., Rippner, D.A. 2023. Vineyard soil texture and pH effects on Meloidogyne hapla and Mesocriconema xenoplax. Agrosystems, Geosciences & Environment. 6(4). Article 20450. https://doi.org/10.1002/agg2.20450.
DOI: https://doi.org/10.1002/agg2.20450

Interpretive Summary: Plant parasitic nematodes are costly pests that cause global crop loss of over $100 billion dollars. Previously it was thought that the large populations of ring nematode in Oregon and Northern root-knot nematode in Washington vineyards were caused by differences in soil characteristics. We found that soil texture had no influence on both nematodes’ population growth. We found that Northern root-knot nematodes that live inside of the roots thrived in acidic (low pH) soil than alkaline (high pH) soil. Soil pH had no effect on ring nematodes that live outside of the roots. These results will help generate parasitism risk maps, and also help wine grape growers make sound vineyard planting decisions.

Technical Abstract: Northern root-knot nematode (Meloidogyne hapla) and ring nematode (Mesocriconema xenoplax) are the most prevalent plant-parasitic nematodes of wine grapes in the Pacific Northwest, but M. hapla is most important in eastern Washington (WA) and M. xenoplax in western Oregon (OR). These regions differ edaphically where WA soils are minimally weathered and alkaline while OR soils are highly weathered and acidic. To examine the effect of soil texture and pH on nematode reproduction, an alkaline, sandy loam soil (pH 7.9) from WA and an acidic loam soil from OR (pH 5.4) were modified to the other pH extreme, and to a middle pH of 6.9. Tomatoes were planted into each soil/pH combination, and either 500 M. hapla second-stage juveniles or M. xenoplax individuals were added to each pot. After seven weeks, plants were harvested, three roots collected for analysis, remaining roots and leaves dried and weighed, and nematode population densities determined as eggs on roots (M. hapla) and nematodes in soil (M. xenoplax). Soil texture (sandy loam or loam) had no effect on either nematode, but M. hapla reproduction was greater in the lowest pH soil while M. xenoplax was unaffected by soil pH. Mesocriconema xenoplax parasitism reduced root length and root tip number, whereas M. hapla increased root mass in the highest pH WA soil. It appears vineyard soil texture in the Pacific Northwest is not a determining factor in population growth of these nematodes, but under these conditions, M. hapla performed better at low pH.