Preliminary survey of plant-parasitic nematodes associated with grapevines in Blenheim, New Zealand

Plant-parasitic nematodes threaten horticultural crops, causing damage by feeding on plant roots, reducing yields, and affecting global food security. We present preliminary results on nematode genera found in soil around two varieties of grapevine (Sauvignon blanc and Pinot noir) with different rootstocks (101-14, SO4, 5C, Riparia Gloire, 3309, Schwarzmann) in ten vineyards located in Blenheim, part of the largest grape-growing area in New Zealand. Soil samples were collected, and nematodes were extracted using a modified centrifugal-flotation technique. Nematode counting and morphological identification to genus level was conducted based on characteristics such as stylet size and overall body shape. Soil texture analysis was performed, and the influences of grape variety and rootstock as well as soil type on nematode diversity were assessed. Four genera of plant-parasitic nematodes, including Pratylenchus, Paratylenchus, Helicotylenchus, and Criconomella, were recovered from the vineyard soils and a snapshot of relative abundance was determined. Differences in the nematode genera and their relative abundance among varieties and rootstocks were found, which suggests potential interactions between nematode genera and grapevine rootstocks/scions. This preliminary survey provides updated information on nematodes since the last survey conducted 20 years ago in New Zealand. This work indicates the presence of various genera of plant-parasitic nematodes in soils around grapevines grown around Blenheim, New Zealand. These findings highlight the need for further research to understand the interactions between nematodes, grape varieties, and rootstocks. The importance of addressing this knowledge gap for biosecurity measures and potential implications on grapevine growth and vineyard productivity is discussed.