2023 Willamette Valley Pest Management Guide for Cherries

This guide lists recommendations for insect, mite and disease control in cherry orchards. The chemicals, formulations and application rates listed here are based on label directions, research and orchard experience.

Pest management depends on producers and their knowledge of the orchard and its characteristics. Producers must weigh several factors: cultivar, tree size, tree density, canopy characteristics, pest complex and pest history. Consider all these factors when choosing which chemicals to apply and at what rates. Other variables include the amount of water used per acre, and the method of application.

Trade name products are mentioned as examples only. Occasionally, manufacturers register different formulations of a product that contain a different concentration of active ingredient. This does not mean that OSU Extension either endorses these products or intends to discriminate against products not mentioned. Consult product labels to determine whether their use confers advantages over the products listed in this guide.

Always refer to the pesticide label for use instructions. It is the legal document.

Producers ask two common questions about the chemical control of insects and diseases:

• “How much chemical do I use per acre?”
• “What is the least amount of water I need per acre to apply in my concentrate sprayer?”

The schedule below suggests an amount of formulated product to use per acre, and not the amount of active ingredient. This amount is based on a “typical” orchard of middle age and average tree density, with moderate pest pressure. Less product may be needed in 1- to 4-year-old orchards. Conversely, more chemical (within label limits) may be required for large, mature trees experiencing heavy pressure from multiple pests.

It takes less spray to get good coverage on an orchard with immature trees with limited canopy, but this does not affect the rate of application by volume. For most ground-applied applications, apply products in a minimum of 100 gallons of water per acre. Spray systems that use sensors to deactivate nozzles when there are gaps in the canopy can reduce drift and pesticide use, especially in young orchards. See Sensor Sprayers for Specialty Crop Production, PNW 727.

Always calibrate sprayers to tree size to improve coverage, reduce waste and avoid drift. See Six Steps to Calibrate and Optimize Airblast Sprayers for Orchards and Vineyards, PNW 749.

Many insecticide labels today list the minimumamount of water needed per acre in concentrate sprays of insecticides. Labels also tell users how to calculate the amount of chemical needed per acre in a concentrate sprayer. Check the label before spraying! Some label directions indicate dilute applications only, such as the dimethoate labels for cherry fruit fly control. Also:

• Make sure any tank-mixes of pesticides are compatible. For example, the elevated pH of some boron spray solutions weakens many insecticides. Water hardness above 250–350 ppm can also negatively affect pesticide efficacy, particularly for certain herbicides.
• Use adjuvants and spreader stickers with caution.
• Rotate pesticides by mode of action (group); do not become reliant on a single group for control.
• In this guide, mode of action (MoA) for insecticides is based on the Insecticide Resistance Action Committee (IRAC) classification. Fungicide mode of action is based on the Fungicide Resistance Action Committee (FRAC) classification. Herbicide site of action is based on the Herbicide Resistance Action Committee (HRAC) classification.
• Premix products may have reduced rates of active ingredients, and may contribute to development of resistance.

Important: Be aware of regulations governing the application of pesticides outlined in the EPA Worker Protection Standard, particularly the Application Exclusion Zone, which is enforced by Oregon Occupational Safety and Health. All pesticide labels provide orchard reentry intervals and personal protection equipment information.

Apply pesticides judiciously and promote good relationships with neighbors.

Cherry pest control recommendations

Use only one material except where a combination is indicated. Follow label precautions when tank-mixing oils, fungicides, and insecticides. Materials are not listed in order of preference. Copper-based products alone have not worked well under conditions favorable for bacterial canker development.

Stage 0: Dormant season

Shothole
Note: Use of copper may increase bacterial canker in some orchards. If you use these products, apply the first spray in October before the fall rains and again in early January. Do not graze sheep in orchards sprayed with coppers. Toxic amounts of copper can build up in orchard soils after decades of use.

Bordeaux 12-12-100: See footnote 1

Footnotes

1. Bacteria resistant to copper products have been detected in many Willamette Valley crops. Some growers report control of bacterial canker by the application of bordeaux 12-12-100 in October and January; others report little or no control. Some research trials have shown that copper products can significantly increase this disease. If you choose to use copper-based products, thoroughly spray the trunks and lower scaffolds as well as the upper branches, and limit total number of applications. Bordeaux 12-12-100 means 12 lb of copper sulfate plus 12 lb of hydrated lime in 100 gal of water. In any bordeaux formula, the ingredients always are listed in the same order—copper sulfate, hydrated lime, then gallons of water.
2. Young trees not being sprayed for brown rot may need an application of fungicide during bloom for adequate control of cherry leaf spot. This is more of a problem in high rainfall areas or during some years.
3. Fungal pathogens have shown resistance to several fungicides when one is used exclusively. Alternate or tank-mix with fungicides with different modes of action. Fungicides from different FRAC groups have different modes of action. Some products may already be a mix of two different fungicides. One or two applications during bloom may adequately control brown rot when products with systemic (translaminar) activity are used.
4. Shothole borer can have three generations in Valley orchards. Look for new adults and/or sawdust pushed from emergence holes in late winter, June/July, and again in September/October. This pest prefers young and/or stressed trees. Cultural controls include pruning of infested limbs, and severely infested trees should be removed before adult beetles emerge in spring. Maintaining tree vigor and health with a good nutrition program helps trees resist shothole borer. Chemical control is difficult and consists of spot-treating trunks and limbs when adults are emerging and reinvading during delayed dormant.
5. Syneta beetle is a small, pale leaf- and fruit-feeding beetle that causes fruit scarring from shortly after pollination through the time cherries are pinhead size. It is a localized problem in the Valley and within orchard blocks. Adults begin emerging and feeding in orchards before bloom or as late as early fruit set. First emergence has been as early as April 6 or as late as early May depending upon elevation and slope of individual blocks. Beetles may be present for 4–6 weeks in an orchard. Best time for control is PREBLOOM (popcorn) if beetles are present. Imidan was historically the favored insecticide but can only be used on tart cherries. Do not introduce bees for 5 days post spray of this insecticide because of possible residues and associated bee kills. DO NOT APPLY IMIDAN TO TREES IN BLOOM! Spinosad (Entrust/Success) compounds have less risk for pollinators, but avoid spraying when bees are active. Ground emergence cages and “tap trays” for pear psylla monitoring are used to determine presence of Syneta.
6. Alternate group 11 fungicides with a fungicide that has a different mode of action. Do not use more than two sequential applications. Sprayers used for Abound, QuiltXcel, Quadris, Quadris Top or TopGuard EQ should not be used on apples such as Gala, Cox’s Orange Pippin, and McIntosh. Even a small amount of drift can severely impact these apple trees.
7. Good information on the control of shothole in sweet cherry is lacking. Much of our information is derived for the same disease on peaches or almonds. Other materials than those recommended here also may be effective. Applications past shuck split may be needed in years when heavy spring rains continue past bloom.
8. Monitor for spotted wing drosophila (SWD) with commercial traps. Homemade traps can also be effective. orUse clear, quart-sized plastic deli cups with lids (or any plastic container). Drill or puncture about 10 3⁄16-inch holes near the rim of the cup for fly entry. Bait traps with pure (unflavored) apple cider vinegar plus a drop of unscented liquid soap or use commercial lures Hang the trap in a shady, cool location within the tree canopy. Place traps just before fruit starts to change to its ripening color. Check traps weekly. Various kinds of flies will be captured in this nonspecific trap, so learn to identify SWD. Males are easily identified by the spots on the wings Treatment thresholds have not been established, but preventive measures should be taken when the first SWD is captured and fruit starts to ripen. Chemical controls target adults and can help prevent females from laying eggs in fruit, but have limited effect on larvae feeding within the fruit. Many resources on management of SWD are available in the OSU Extension Catalog.

Follow the ‘RULES’ for fungicide stewardship

Rotate or mix fungicides of different chemical groups.

Use labeled rates.

Limit total number of applications.

Educate yourself about fungicide activity, mode of action and class — as well as resistance management practices.

Start a fungicide program with multisite mode of action materials.

OSU resources for plant protection

Information on plant protection is available from several sources at Oregon State University:

• OSU Integrated Plant Protection Center. Online weather data and degree day information for insect pests and diseases
• Pacific Northwest Plant Disease Management Handbook
• Pacific Northwest Insect Management Handbook
• Pacific Northwest Weed Management Handbook

Using pesticides safely

Always read the label

The single most important approach to pesticide safety is to read the pesticide label before each use and then follow the directions. If still in doubt after reading the label, contact a person qualified to help evaluate the hazard of the chemical and its use. Qualified people include Extension specialists, county educators, pesticide product representatives, and retailers.

Pesticides are toxic and should be handled with care — but they can be used safely if you follow recommended precautions. Follow all label requirements, and strongly consider any recommendations for additional personal protective clothing and equipment. In addition to reading and following the label, other major factors in the safe and effective use of pesticides are the pesticide applicator’s qualifications, common sense, and positive attitude. Always take all safety precautions when using pesticides.

In case of accidents involving pesticides, see your doctor at once. It will help your doctor to know exactly which pesticide is involved. The label on the container gives this information. Take to the physician the pesticide label or information from the label, such as the product name, registration number of the U.S. Environmental Protection Agency, common name and percentage of active ingredient, and first aid instructions. If the label cannot be removed, take along the pesticide container (if not contaminated), but do not take it into the hospital or doctor’s office.

Pesticide safety checklist

• Use pesticides only when necessary and as part of an Integrated Pest Management program.
• Always read the label and follow the instructions.
• Do not allow children to play around sprayers or mixing, storage and disposal areas.
• Wear appropriate protective clothing and equipment.
• Never eat, drink or smoke while handling pesticides.
• Avoid drift into nontarget areas and pesticide runoff into streams, rivers, lakes, irrigation ponds and canals.
• Avoid spilling materials on skin or clothing.
• Have access to clean water, soap and first-aid supplies.
• Keep pesticides in a dry and locked storage area away from food and feed.
• Triple rinse or pressure rinse empty containers and dispose or recycle in accordance with state and local regulations.
• Stay out of recently sprayed areas until the spray has dried, and observe the restricted entry intervals
• specified on the pesticide label.
• Follow the pre-harvest interval on the pesticide label before harvesting crops or gardens and before allowing livestock to graze fields.

Emergency response for exposure and spills

• For any pesticide exposure emergency, dial 911.
• First aid for exposure is indicated on the pesticide label.
• For information on poison emergency treatment call the National Poison Center Poison Help Line at 1-800-222-1222.
• For emergency information related to pesticide spills contact the Oregon Emergency Response System at 1-800-452-0311.

Non-emergency information

• General pesticide information — The National Pesticide Information Center provides objective, science-based information about pesticides and pesticide-related topics. Call 1-800-858-7378.
• Pesticide licensing and regulation — The Oregon Department of Agriculture regulates most aspects of pesticide use in the State of Oregon. Call 503-986-4635.
• Worker protection — The federal Worker Protection Standard for Agricultural Pesticides protects agricultural workers from pesticide exposure at work. The Oregon Occupational Safety and Health Administration is the state agency responsible for administering the WPS in Oregon. For information on WPS requirements for employers, call 1-800-922-2689.
• Pesticide waste — The Oregon Department of Environmental Quality regulates the disposal of pesticide waste in the State of Oregon. Call 503-229-5263. Most area chemical distributors offer plastic pesticide container recycling. For information on container preparation, contact your chemical supplier.