General Instructions for Fruit Tree Sample Collection

  1. Immediately place the sample in a sealed plastic bag (e.g. Zip-Loc). Label bag (tree, row, grower, GPS etc.).
  2. Do not add additional moisture in the bag.
  3. Do not allow the bag to sit in the sun (the samples heat very quickly).
  4. Keep the samples cool and shaded.
  5. If you use ice packs, do not place the bags with leaf samples directly against the ice pack. This will freeze the tissue and the lab will not be able to test the sample reliably. Use several layers of paper or bubble wrap to insulate the leaves.

NOTE: The virus distribution in plants is uneven, particularly with recent infections, and the virus concentration changes from season to season. The type of tissue and season are the critical factors influencing reliable results. Dormant bud sticks are often one of the best tissues for virus detection. Generally the virus concentration is reduced in the hot summer season (with exceptions). Suggestions for collecting different sample tissues are provided below for testing major stone and pome fruit viruses/diseases.

Stone Fruits

Sample collection for testing Ilar (PVA, PNRSV, APLPV), poty (PPV), Nepo (CLRV, ToRSV, TRSV), Chera (CRLV), Tricho (ACLSV, CMLV), Fovea (ApLV), Capillo (CVA, ASGV) and CGRMV, CRMaV, CNRMV, CTLaV viruses.

Type of Sample Collection Time Sample Description
Dormant bud sticks End of Jan. until bud break 8 – 10 inches at the base of the 1-year-old wood. Samples close to leader generally give more consistent results. Collect one stick each from all major scaffold limbs and package together in a zip lock bag.

 

Flower and leaf buds Bud swell to popcorn stage Collect sample from all major scaffolds and limbs. Each individual sample must have at least 6 buds. Package individual samples together in a zip lock bag.

 

Branches 2 weeks after full bloom until end of Aug. 8 to 10 inches of 1-year-old wood or the base of the current season’s growth (with leaves attached) are the best samples. Samples close to leader generally give more consistent results. Collect sample from all the symptomatic limbs. For non-symptomatic trees collect a sample from each major scaffold limb and package together. For testing Ilar viruses, collect the samples prior to summer (from full bloom until mid-June)

Sample collection for testing Little cherry disease (Little Cherry Virus and Western X Phytoplasma). The results are more reliable when samples are collected near or after commercial harvest. During growing season, flag limbs with suspicious symptoms for sample collection later in the season.

Type of sample Collection time Sample Description
Dormant bud sticks End of Jan. until bud break 8 – 10 inches at the base of the 1-year-old wood. Samples close to leader generally give more consistent results. Collect one stick each from all major scaffold limbs and package together in a zip lock bag.

 

Flower and leaf buds Bud swell to bud popcorn stage Collect sample from all major scaffolds and limbs. Each individual sample must have at least 6 buds. Package individual samples together in a zip lock bag.

 

Branches Near to harvest or aftercommercial harvest 8 to 10 inches of 1-year-old wood or the base of the current season’s growth (with leaves attached) are the best samples. Samples close to leader generally give more consistent results. Collect sample from all the symptomatic limbs. For non-symptomatic trees, collect sample from each major scaffold limb and package together. The results are more reliable when samples are collected near or after commercial harvest. During the growing season, flag limbs with suspicious symptoms for sample collection later in the season.

Pome Fruits

Sample collection for testing Ilar (ApMV), Nepo (ToRSV), Chera (CRLV), Tricho (ACLSV), Fovea (ASPV) and Capillo (ASGV) viruses.
Type of sample Collection time Sample Description
Dormant bud sticks End of Jan. untilbud break 8 – 10 inches at the base of the 1-year-old wood. Samples close to leader generally give more consistent results. Collect one stick each from all major scaffold limbs and package together in a zip lock bag.
Flower and leaf buds Bud swell to bud popcorn stage Collect sample from all major scaffolds and limbs. Each individual sample must have 6 buds at least. Package individual samples together in a zip lock bag.
Branches 2 weeks after full bloom untilend of June 8 to 10 inches of 1-year-old wood or the base of the current season’s growth (with leaves attached) are the best samples. Samples close to leader generally give more consistent results. Collect sample from all the symptomatic limbs. For non-symptomatic trees collect a sample from each major scaffold limb and package together.

PDV- Prune Dwarf Virus, PNRSV- Prunus Necrotic Ring Spot Virus, APLPV- American Plum Line Pattern Virus, PPV- Plum Pox Virus, CLRV- Cherry Lead Roll Virus, ToRSV- Tomato Ring Spot Virus, TRSV- Tobacco Ring Spot Virus, CRLV- Cherry Rasp Leaf Virus, ACLSV- Apple Chlorotic Leaf Spot Virus, CMLV- Cherry Mottle Leaf Virus, ApLV- Apricot Latent Virus, CVA- Cherry Virus A, ASGV- Apple Stem Grooving Virus, CGRMV- Cherry Green Ring Mottle Virus , CRMaV – Cherry Rusty Mottle associated Virus , CNRMV- Cherry Necrotic Rusty Mottle Virus, CTLaV- Cherry Twisted Leaf associated Virus, ApMV- Apple Mosaic Virus, ASPV- Apple stem Pitting Virus