Compiled by Tianna DuPont, WSU Extension. Reviewed by Scott Harper, WSU Plant Pathology; Tobin Northfield, WSU Entomology; Rachel Bomberger, WSU Pesticide Publication Review. April 1, 2022
It is critical to manage broadleaf weeds in cherry orchards to mitigate the risk of X-disease phytoplasma. Several perennial weeds (clover, alfalfa) and annual/biennial weeds (flixweed, dandelion, chickweed, lambsquarter, puncture vine, mallow and tumble mustard) are alternative hosts for x-disease phytoplasma (Jensen 1969, Harper 2021). New research shows that leafhoppers tend to prefer ground cover (versus trees) and so management of host species on the orchard floor is particularly important (Northfield 2021). Rootsuckers should also be targeted as they tend to have a high concentration of the pathogen when trees are infected.
Fig 1. Perennial weed alternative hosts for X-disease phytoplasma.
Fig 2. Annual weed alternative hosts for X-disease phytoplasma.
Time one spring broadleaf weed spray approximately the 2nd-3rd week in May when weeds are small and before they develop seeds. A spring root sucker spray and a fall weed spray are another option. Pre-emergent herbicides (e.g. Prowl H20, Solicam DF) and non-contact residual herbicides (e.g. Alion, Matrix, Pindar GT), and contact herbicides (eg. Roundup PowerMax, Stinger, Venue, Rely 280) are labeled for cherries. In addition to the tree row area generally targeted for weed management, consider herbicide applications that reduce broadleaf weeds in the grass strip using products that won’t kill grasses. Gramoxone SL 2.0, and Venue are options for root sucker control if sprayed while the root suckers are still green and haven’t turned woody.
X-disease phytoplasma https://treefruit.wsu.edu/crop-protection/disease-management/western-x/
Little cherry virus https://treefruit.wsu.edu/crop-protection/disease-management/little-cherry-disease/
Symptoms Gallery https://treefruit.wsu.edu/crop-protection/disease-management/western-x/symptoms-gallery/
Vector Gallery https://treefruit.wsu.edu/vector-gallery/
Symptoms and Sampling Videos
Scouting and Sampling for Little Cherry Disease
Symptoms of Little cherry virus and X-disease phytoplasma https://treefruit.wsu.edu/videos/symptoms-of-little-cherry-virus-and-x-disease-phytoplasma/
Symptoms of X-disease Phytoplasma in Stone Fruit https://treefruit.wsu.edu/videos/symptoms-of-x-disease-phytoplasma-in-stone-fruit/
Where to send samples
Resources in Spanish
Fitoplasma X (Western X) https://treefruit.wsu.edu/crop-protection/disease-management/western-x/fitoplasma-x-western-x/
Virus de la Cereza pequeña (LChV) https://treefruit.wsu.edu/crop-protection/disease-management/little-cherry-disease/virus-de-la-cereza-pequena-lchv/
Enfermedad de la cereza pequeña en cerezos. https://treefruit.wsu.edu/videos/enfermedad-de-la-cereza-pequena-en-cerezos/
X-disease and Little Cherry Virus Scouting and Sampling Guide* https://treefruit.wsu.edu/crop-protection/disease-management/western-x/sampling-guide/
Síntomas de Fitoplasma X y Little Cherry Virus. https://treefruit.wsu.edu/videos/sintomas-de-fitoplasma-x-y-little-cherry-virus-2/
Corina Serban, WSU Extension (509) 574-1595 email@example.com
Tianna DuPont, WSU Extension (509) 293-8758 firstname.lastname@example.org
Bernardita Sallato, WSU Extension (509) 439-8542 email@example.com