Tips on scouting and sampling for X-disease and Little cherry disease which cause small, pale unmarketable fruit in cherries. By WSU Extension, OSU Extension and the Good Fruit Grower. Funding provided by a grant from the Washington Tree Fruit Research Commission. Published June 17, 2020.
Text Transcript with Description of Visuals
| Audio | Visual |
|---|---|
| Music plays | Camera pans over the limb of a cherry tree, showing cherries that are small, lightly colored, and misshapen. |
| X-Disease phytoplasma and Little Cherry Disease cause small misshapen fruit. | Camera pans over the limb of a cherry tree, showing cherries that are small, lightly colored, and misshapen. |
| Fruit often have poor color development. | Camera pans upwards on the cherry tree to show more cherries which have yellow patches. |
| Symptoms are clearest close to harvest when non-symptomatic fruit are ripe. | Close up video of cluster of non-symptomatic cherries which are full, large, dark red, and properly shaped. Text appears on screen that says “Tree with healthy fruit”. The shot changes to a close up video of a cluster of cherries that are light red with yellow patches, misshapen, and much smaller than the healthy fruit. Text appears on screen that says “Tree with symptomatic fruit”. |
| Small fruit may be on some limbs but not others or vary within a fruit cluster. | Camera pans over the limbs of a cherry tree showing a some fruit that is dark red and full, alongside cherries that are small, misshapen, and lightly colored. |
| An insipid, not sweet taste is typical. | A hand reaches up to grab one of the small, lightly colored cherries from the limb of a cherry tree. The camera pans to the face of the man picking the cherry. The man puts the cherry in his mouth, chews, and makes a displeased face at the taste of the cherry. |
| When scouting it is important to look at every tree and every row in order to find new infection. Make sure to look at the top as well as the bottom of the trees. | Three men in orange safety vests ride on 4-wheelers down adjoining rows of a cherry orchard. As they slowly ride down the rows, they look at the trees closely, assessing them for symptoms. |
| The best time to detect symptoms is right before harvest, up to a week before, when symptoms are most obvious. | Three people walk on foot through a cherry orchard, looking at the trees to assess them for symptoms. They carry yellow tags in order to flag symptomatic trees. |
| Mark suspect trees and label them so you can identify them and match them with you samples. | A woman wraps bright pink flagging tape around the trunk of a symptomatic cherry tree and ties the tape in a knot. She then puts a bright pink tree label with a numeric code on it around the symptomatic branch. |
| The easiest method is with well labeled flagging tape, but be careful, flagging tape can sometimes disappear in the orchard. | A man wraps bright pink flagging tape around the trunk of a symptomatic cherry tree and ties the tape in a knot. |
| Some like to mark the trunk and suspect limbs with spray paint and add a mark if the tree is positive. | A woman sprays three short horizontal lines of bright yellow spray paint onto the trunk of a tree. She then makes a longer vertical line going through the middle of the three horizontal lines. |
| Others like to mark the tree with flagging tape, and then also mark the limb with a loose zip-tie that’s most symptomatic. | A pair of hands on screen write a label on a roll of flagging tape with a marker. |
| That allows them to come back and sample in that symptomatic area, even if folks have harvested that fruit. | A pair of hands tear off a piece of the labelled flagging tape and tie it around a tree. The hands then place a red zip tie around one limb of the tree, which shows small, light colored cherries. |
| A third strategy is to mark with tape and large tags made of waterproof paper. | A man kneels down in front of a cherry tree and wraps yellow flagging tape around the trunk of the tree. |
| Marking the waterproof tag with permanent ink helps reduce fade. | The man takes a bright yellow waterproof tag attached to a piece of twine and ties it onto the lower part of a tree limb. |
| I like to mark the trees with tape and then give it a code with a printed tree label. | A woman wraps bright pink flagging tape around the trunk of a symptomatic cherry tree and ties the tape in a knot. She then puts a bright pink tree label with a numeric code on it around the symptomatic branch. |
| I also mark the location with a GPS so I can come back to find that exact tree. | The woman uses a handheld GPS device to find and mark the location of the tree. |
| To sample trees with symptoms, sample from symptomatic limbs. Take four or five inch cuttings with leaves and fruit stems. Fruit stems are especially good tissue to extract the pathogen from. | A woman uses pruning shears to take samples from a symptomatic tree. She snips off several small limbs containing leaves and fruit, then trims them down to around 5 inches in length. |
| Place cuttings in a well labeled bag with a label that corresponds to your tree label. | The woman places the tree cuttings into a plastic bag which is labeled with the same numeric code that was seen on the tree label. |
| Keep samples cool by keeping them in a cooler as you go or putting them in a cooler in your truck at the end of the row. | The woman places the plastic bag of samples into a small Styrofoam cooler with an ice pack in it. |
| For trees without symptoms, take four or five inch cuttings, one from each leader or side of the tree. Include leaves as well as fruit stems. | A woman uses pruning shears to take samples from a non-symptomatic tree. She snips off several small limbs containing leaves and fruit from different sides of the tree, then trims them down to around 5 inches in length. |
| Make sure your bag is labeled and that the tree is labeled with the same code. | The woman places the tree cuttings into a plastic bag which is labeled with the same numeric code that was seen on the tree label. |
| Deliver your samples right away or send them overnight with a cold pack. | The woman places the plastic bag of samples into a small Styrofoam cooler with an ice pack in it. Text on screen reads “Send samples to Washington: Eurofins Cascade Analytical. 1008 W Ahtanum Rd. Union Gap, WA 98903. (509) 454-7707 For drop locations visit www.cascadeanalytical.com Oregon: The Oregon State University Plant Clinic bpp.oregonsstate.edu/plant-clinic |
| Music plays | Information about funding, videography, and authors appears on screen. |
Link to YouTube video: Scouting and Sampling for Little Cherry Disease
For more information and support materials, see
X-disease Phytoplasma and Little Cherry Virus Scouting and Sampling Guide
Contacts
Tianna Dupont, WSU Extension (509) 293-8758 tianna.dupont@wsu.edu
Bernardita Sallato, WSU Extension (509) 439-8542 b.sallato@wsu.edu
Ashley Thomson, OSU Extension (541) 296-5494 Ashley.Thompson@oregonstate.edu
Karen Lewis, WSU Extension (509) 760-2263 kmlewis@wsu.edu
