If you have trees with small, misshapen or poor colored fruit and suspect Little Cherry or X-disease, sample if the disease has not been previously confirmed in the block. For a tutorial on sampling for X-disease and Little Cherry Disease see Scouting and Sampling for Little Cherry Disease.
Material to sample
Submit four five-inch cuttings from the diseased limb(s) including young woody tissue (pencil size previous season wood), leaves and fruit stems.
New information!
- Woody material should be from the previous season or older because we have found that current season growth can have variable pathogen concentrations.
- New research shows that leaves may test negative even though the wood they’re attached to is positive, therefore leaves by themselves are not recommended.
- Pencil sized wood from the previous season and fruit stems are the best tissue to sample.
Note: The information is based on current on-going research.
Where to sample:
Trees with symptoms: Sample from symptomatic limbs.
Trees with no symptoms: Sample from each leader.
When to sample:
The week before harvest to mid-August.
Sample condition:
Keep tissue moist and cool (e.g. package with a cold pack). Old or dried tissue is more likely to have false negatives.
Where to send samples:
See labs page
Download sampling fliers:
Scouting flier vf (2021.02.04) Muestreo de X Fitoplasma y Little Cherry Virus flier WSU OSU (2021.02.04) [pdf]
Additional information
X-disease webpage
Little Cherry Virus webpage
Nursery Prevention of X-disease Phytoplasma and Little Cherry Virus Recommendations
BMPs for tree removal for X-disease and Little Cherry Virus infected trees
Case studies on tree removal for X-disease phytoplasma and Little cherry virus
Alternative weedy hosts for X-disease phytoplasma.
Videos
Symptoms of Little Cherry Virus and X-disease Phytoplasma.
Síntomas de Fitoplasma X y Little Cherry Virus.
Symptoms of X-disease Phytoplasma in Stone Fruit.
Síntomas de Fitoplasma X en Frutas de Hueso.
Contacts
WSU Extension
(509) 574-1595
corina.serban@wsu.edu
WSU Extension
(509) 293-8758
tianna.dupont@wsu.edu
WSU Extension
(509) 439-8542
b.sallato@wsu.edu
Department of Plant Pathology, Washington State University
(509) 786-9230
scott.harper@wsu.edu
WSU Entomology
(509) 293-8789
tnorthfield@wsu.edu
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