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Spring and Fall Broadleaf Herbicide Applications a Component of Integrated X-disease Management

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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.

Perennial Weeds

Fig 1. Perennial weed alternative hosts for X-disease phytoplasma.

Annual Weeds

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.

Additional information

Resource pages

X-disease phytoplasma http://treefruit.wsu.edu/crop-protection/disease-management/western-x/
Little cherry virus http://treefruit.wsu.edu/crop-protection/disease-management/little-cherry-disease/
Symptoms Gallery http://treefruit.wsu.edu/crop-protection/disease-management/western-x/symptoms-gallery/
Vector Gallery http://treefruit.wsu.edu/vector-gallery/

Symptoms and Sampling Videos

Scouting and Sampling for Little Cherry Disease
http://treefruit.wsu.edu/videos/scouting-and-sampling-for-little-cherry-disease/
Symptoms of Little cherry virus and X-disease phytoplasma http://treefruit.wsu.edu/videos/symptoms-of-little-cherry-virus-and-x-disease-phytoplasma/
Symptoms of X-disease Phytoplasma in Stone Fruit http://treefruit.wsu.edu/videos/symptoms-of-x-disease-phytoplasma-in-stone-fruit/

Where to send samples

Labs testing for Little Cherry Virus and X-disease Phytoplasma

Resources in Spanish

Fitoplasma X (Western X) http://treefruit.wsu.edu/crop-protection/disease-management/western-x/fitoplasma-x-western-x/ 

Virus de la Cereza pequeña (LChV) http://treefruit.wsu.edu/crop-protection/disease-management/little-cherry-disease/virus-de-la-cereza-pequena-lchv/

Enfermedad de la cereza pequeña en cerezos. http://treefruit.wsu.edu/videos/enfermedad-de-la-cereza-pequena-en-cerezos/

X-disease and Little Cherry Virus Scouting and Sampling Guide* http://treefruit.wsu.edu/crop-protection/disease-management/western-x/sampling-guide/

Síntomas de Fitoplasma X y Little Cherry Virus. http://treefruit.wsu.edu/videos/sintomas-de-fitoplasma-x-y-little-cherry-virus-2/

Contacts

Corina Serban, WSU Extension (509) 574-1595   corina.serban@wsu.edu

Tianna DuPont, WSU Extension (509) 293-8758 tianna.dupont@wsu.edu

Bernardita Sallato, WSU Extension (509) 439-8542 b.sallato@wsu.edu

Washington State University