Location: Horticultural Crops Disease and Pest Management Research Unit
Project Number: 2072-22000-046-038-G
Project Type: Grant
Start Date: May 1, 2023
End Date: Oct 31, 2024
Objective:
1. Identify and sample 120 vineyards across Oregon for presence of plant-parasitic nematodes.
2. Identify plant-parasitic nematodes present and their geographic distributions in Oregon.
3. Relate site characteristics, such as cropping history, soil type, and viticultural practices to abundance of nematode species.
Approach:
Objective 1. PIs and cooperators will rely on their regional knowledge and outreach contacts to identify 120 vineyard sampling sites throughout Oregon. The number of sites per region will be relative to its acreage compared to the state total. Of the 120 sites, 40 will be sampled in each of the three growing seasons. In each growing season, sites will be sampled twice (April and October) to better capture all potential nematode species and population dynamics. At sampling time, composite soil samples will be collected in the vine row down to 12-18 in. along two 100-ft transects in the block. The spring soil sample will be split into two subsamples, with one sent to an analytical laboratory for characterization of physical and chemical properties, and the other reserved for nematode analyses.
Objective 2. Plant parasitic nematodes will be extracted from 250 g soil samples from each vineyard by decant sieving and sugar centrifugation. Nematodes will be identified to genus by observing morphological characteristics using an inverted microscope. To identify at the species level, individual nematodes will be picked from samples and DNA extracted. Depending upon the genus, published primers will be used to amplify regions of the nematode that are diagnostically important. Amplified regions will be compared to available data in Genbank to determine the identity of the nematode. For each population, 10 individuals per genus we be identified using this method.
Objective 3. Sites will be grouped into larger regions according to designations used in the annual vineyard and winery report (IPRE, 2022). Site characteristics such as plant material (rootstock/cultivar), previous cropping history, soil type, and other relevant viticultural practices will be recorded from vineyard manager, observation, and/or analytical assays. Frequency distributions will be constructed for each identified nematode species with classes defined by nematode concentrations, and presented as functions of region, soil type, cropping history, etc. as dictated by data.
