Nematodes
Nematodes are wormlike non-segmented invertebrate animals found in marine, freshwater, and terrestrial habitats. Plant-parasitic nematodes have a cell piercing feeding apparatus called a stylet, which is used to extract nutrients from the plant cell. Plant-parasitic nematodes feed on roots, reducing vigour and yield of the vine usually in irregular patterns across the vineyard. Damage patterns are frequently associated with soil textural differences. Nematodes create openings in roots through which other microorganisms can enter, and some species are able to transmit viruses from one vine to another. All these factors increase the susceptibility of plants to environmental stress, including drought stress and winter injury. Nematodes are transmitted by anything that can move soil, including machinery, wind, and water. There are six main groups of plant-parasitic nematodes that cause damage to grapevines; dagger, root-knot, citrus, lesion, ring, and stubby root nematodes.
Practical
Cover crops and plant parasitic nematodes (Fact sheet)
https://www.wineaustralia.com/getmedia/d3f29dff-fbaa-4959-8d9d-2555c7e62335/201206-cover-crops-plant-parasitic-nematodes
Nematodes in Australian soils – Vitinotes
https://www.awri.com.au/wp-content/uploads/nematodes_in_aust_soil.pdf
Nematodes – general guide
https://grapes.extension.org/nematodes/
Sampling for Nematodes – Vitinotes
https://www.awri.com.au/wp-content/uploads/nematodes_sample_method.pdf
Technical
Excerpts from “Grape Growers’ Handbook”, some information links
http://www.wine-grape-growing.com/wine_grape_growing/managing_nematodes_vineyards/controlling_vineyard_nematodes.htm
Impact of nematodes on grapevine growth and productivity: Current knowledge and future directions, with special reference to Australian viticulture. (research paper)
https://vinehealth.com.au/media/Nematode-article.pdf
Nematodes in Vineyards (USA, extensive information)
http://ipm.ucanr.edu/PMG/r302200111.html
Nematodes in Western Australian Vineyards (Research publication, good diagrams)
https://researchlibrary.agric.wa.gov.au/cgi/viewcontent.cgi?article=1115&context=bulletins