EM 8538    Revised February 2018

The chemicals, formulations, and rates listed here for insect, mite, and disease control are among the best recommendations based on label directions, research, and use experience. Only a thorough knowledge of the blueberry planting, its cultivars, bush size and density, canopy characteristics, pest complex, and past pest problems will enable you to correctly select chemicals, rates, amount of water used per acre, and method of application for optimum pest control. Occasionally, different formulations of a product or like formulations containing a different amount of active ingredient also are registered and effective for use on the pests listed. These products also may be used; we do not intend to discriminate against them. You may wish to consult their labels and determine whether their use confers advantages over the products listed in this guide.

Two questions frequently are asked about the chemical control of insects and diseases: “How much chemical do I use per acre?” and “What is the least amount of water I need per acre to apply in my concentrate sprayer?” Notice that the recommendations below suggest an amount of formulated product (not active ingredient) to use per acre. This amount is based on a “typical” middle age and density blueberry planting with moderate pest pressure. Common sense indicates that less material may be needed for 1- to 4-year-old plantings. Conversely, more chemical (within label limits) may be required for large, mature bushes experiencing heavy pest pressure from multiple pests.

Many insecticide labels today indicate the minimum amount of water needed per acre to apply concentrate sprays of insecticides, as well as how to calculate the amount of chemical needed per acre in a concentrate sprayer. CHECK LABEL BEFORE SPRAYING!

Always refer to the pesticide label for use instructions. It is the legal document regarding rate and use pattern.

Resistance management

The Insect Resistance Action Committee (IRAC) and the Fungicide Resistance Action Committee (FRAC) each has helped to develop codes for insecticides and fungicides, respectively, based on their mode of action and target site. An IRAC code or a FRAC code appears on the front of each pesticide label. To better manage fungicide resistance, do not mix or alternate insecticides with the same IRAC number or fungicides with the same FRAC number in a spray program.

• To view a complete listing of IRAC codes: www.irac-online.org/documents/moa-classification/?ext=pdf

The FRAC codes for various blueberry fungicides are listed at the end of this publication. The FRAC code “M” indicates that the fungicide acts upon multiple sites and has low resistance risk.

• To view a complete listing of FRAC codes: http://www.frac.info/docs/default-source/publications/frac-code-list/fra...

Important Information

Worker Protection Standard (WPS): Under the newly revised WPS (January 2, 2017), agricultural workers and pesticide handlers are required to take annual training by qualified WPS trainers. To mitigate spray drift, the application exclusion zone (AEZ) was recently established for aerial and ground applications. Agricultural employers are required to comply with the new AEZ rule. Handlers’ AEZ requirements became effective on January 2, 2018. For more details about WPS, visit the following Oregon Department of Agriculture website: (https://www.oregon.gov/ODA/programs/Pesticides/RegulatoryIssues/Pages/WP...)

Buffer regulations for the Oregon small fruit industry: In August 2014, a District Court ruling resulted in the continuation of spray buffer regulations near certain bodies of water that were initially put into place in 2004. To obtain up-to-date information on this regulation and to learn whether your fields are close to affected rivers or streams, visit the following Oregon Department of Agriculture website: http://www.oregon.gov/ODA/programs/Pesticides/Water/Pages/Buffers.aspx

Pacific Northwest Pest Management Handbooks for Insect, Plant Disease, and Weed (http://pnwhandbooks.org)

Northwest Berry & Grape Information Network (http://berrygrape.org)

Sequential stages of plant development

1 Dormant: No visible swelling, bud scales completely enclose the inflorescence

2 Bud Swell: Visible swelling of bud, scales separating, flowers still completely enclosed

3 Floral Budbreak: Bud scales separated, apices of flowers visible

4 Floral Budbreak, Prebloom: Individual flowers distinguishable, bud scales abscissed

5 Prebloom: Individual flowers distinctly separated, corollas unexpanded and closed

6 Bloom: Corollas completely expanded and open

7 Petal Fall: Corollas dropped


1. WINTER MOTHS: There are four species of winter moths native to the Northwest. Their life histories are similar in that there is but one generation/year characterized by eggs that overwinter on the trunks and branches of deciduous trees and shrubs. The larvae (inchworms or spanworms) begin emerging as early as March, with egg hatch usually complete by mid-April. The larvae feed on many plants, particularly those of the rose family. Blueberry plantings become infested when moths deposit eggs on plants in late fall and winter and/or when larvae infesting host plants adjacent to the planting are blown in on silken threads. This larval migration often leads growers to believe that previously applied sprays failed to control the pest.

CONTROL: Recognize that larvae are active in March and can burrow into buds, causing damage prior to bud burst. Early-season control is necessary. Infestations of winter moth that are a result of in-field infestations (eggs having overwintered on trunks and limbs of blueberry plants) can be reduced by the dormant oil + insecticide spray during the winter. Careful inspection of buds and newly expanding plant growth from April through early bloom will indicate need for additional sprays. Because larvae are present into June and because the larvae can blow into blueberry plantings from surrounding trees, you must monitor fields even after insecticides have been applied. Repeat sprays may be necessary. Use least-toxic alternatives when pollinators and/or bloom are present.

2. LEAFROLLERS: The most common leafroller in western Oregon blueberries is the orange tortrix. It does direct feeding damage to the berries, provides an entry route for fruit rots, and may become an insect contaminant at harvest. It overwinters as a larva under leaves plastered to the trunks and limbs and among leaf litter of host plants. Most infestations on blueberries occur when moths of the spring generation (flight beginning mid-April and peaking early to mid-June) fly in and deposit eggs on plants.

CONTROL OF LARVAE—PREBLOOM: In-field infestations of larvae should be evaluated and treated (if necessary) from late March to early April, with the April date being on the late side for effective control if mild winter/early spring weather occur.

CONTROL OF LARVAE—LATE JUNE/EARLY JULY: Use pheromone traps to monitor moth activity in individual plantings from May through harvest to help in deciding whether to control larvae. Sprays to control larvae in late June and early July are necessary in caneberries when individual trap catches exceed 70 moths/week or more than 200 moths are caught in a trap by June 1. We do not have adequate information on blueberries at this time. Choice of insecticide will depend on presence of bloom or proximity of harvest. NOTE: If Bacillus thuringiensis is used, two and possibly three applications at 7-day intervals may be necessary to achieve adequate control of heavy infestations. Use of this product with this timing should begin about 3 to 4 weeks prior to anticipated harvest because of its relatively slow action.

CONTROL OF LARVAE—AUGUST THROUGH HARVEST: A second flight begins in late July or early August, with large numbers of moths active through September. Larvae from these flights may infest fruit of the blueberry varieties harvested from mid-August through September. Pheromone traps used as above will help in the decision-making process of whether or not to control orange tortrix.

NOTE: Obliquebanded leafroller adults occasionally are lured to orange tortrix traps. Be sure to distinguish between the two species, as obliquebanded leafroller seldom is a pest in blueberries.

Also, orange tortrix traps will “pull in” males of the orange tortrix from a long distance from the blueberry planting, giving the false impression at times that a large infestation of larvae will follow within 2 to 3 weeks. For this reason, we recommend the placement of “guard” traps a few hundred yards, and in the predominant downwind direction, from the planting. They will intercept moths coming from areas that do not pose a threat to the blueberry field. Do not consider these moths when evaluating the need to spray a given block, but try to identify the source of infestation for future reference.

Finally, always try to verify the presence of larvae in a planting to justify a spray application. Do this by placing a white sheet under a few plants and shaking limbs vigorously. The larvae will hang down on silk threads, eventually falling to the sheet. Rolled leaves and leaves plastered to berries also are indications of infestation.

3. ROOT WEEVILS: Several species of root weevils have been found damaging blueberries in Oregon. Black vine weevil, strawberry root weevil, and obscure root weevil are three of the most common species whose larvae girdle roots, setting back growth tremendously. Adult weevils, although causing negligible injury to the leaves, can be contaminants of fruit.

DETECTION: Depending on the species, adults begin emerging in early May, with 90% emergence usually occurring by mid-June, depending on how warm spring temperatures have been, elevation and slope of the planting, and depth of the insulating sawdust layer. To determine when adults emerge and become active, inspect new sucker growth near crown for leaf notching. With the aid of a flashlight, you can most easily see the adult weevils when they are feeding on foliage on warm, still evenings after sunset.

CONTROL: All weevils are females and have the ability to lay more than 500 eggs during the course of the season. Applications of insecticides to control weevils are timed to 80% to 90% adult emergence but prior to egg laying. This usually is in June.

Weevils are difficult to control with insecticides. Therefore, it is necessary to time foliar sprays carefully. Weevils are active at night. Applications should be made after dark (usually 10 p.m. to after midnight) on warm, still evenings when weevils are on foliage. Two or three sprays approximately 1 week apart are necessary to begin to control an established infestation.

Obviously, you also must consider the presence of bloom and the damage caused by the sprayer to the bloom and by the insecticide to pollinators. Custom programs often must be devised for individual blocks, depending on emergence pattern of the adult weevils, blueberry variety, presence of bloom and pollinators, and proximity to harvest.

Neem, Platinum, or parasitic nematodes can be applied to the soil for control of the larvae in established plantings. Applications made in fall when larvae are young yield best results. Degree of control, however, depends on soil moisture and available irrigation or rainfall. Refer to label for use pattern and precautions.

4. SPOTTED WING DROSOPHILA: The spotted wing drosophila (SWD) is a new and exotic pest that attacks a wide variety of fruits and was first discovered in Oregon in 2009. Adult SWD flies resemble the common vinegar flies found in the kitchen, around compost piles, or on fallen, decaying, and rotting fruit in the fields. Unlike common vinegar flies, SWD flies prefer ripe to overripe fruit on the plant.

A female SWD lays one to three eggs in each fruit; a single female can lay several hundred eggs in her lifetime (each adult lives for an average of 3 to 4 weeks). The larvae feed inside the fruit for about 5 to 7 days until they are ready to pupate. The brownish-yellow pupa is a nonfeeding stage lasting 4 to 5 days. Pupae often remain inside fruit with their respiratory horns sticking out of the fruit for breathing purposes until adult fly emergence. The adult fly then emerges, mates, and begins a new generation of pests. It has been estimated that three to nine generations might occur in Oregon, depending on environmental conditions.

To recognize SWD damage on suspect fruit, look for the following: two hairlike filaments attached to each egg sticking out of fruit (the egg is within the fruit); scarring or spotting on the fruit surface; liquid exuding out of a scar (where eggs were laid) when fruit is squeezed; softening, collapsing, and/or bruising of fruit at the damage site; and small, white larvae and pupae inside the fruit (visible to the naked eye if fruit is opened). Adult flies can be monitored with apple cider vinegar traps, and fruit can be checked for larval infestation with a salt extraction method or a fruit dunk flotation method. For further information on identification and monitoring, visit OSU’s spotted wing drosophila website at http://spottedwing.com

MANAGEMENT STRATEGIES: In addition to the chemical controls mentioned in this publication, the following cultural management strategies and biological control can help mitigate SWD infestations:

• Harvest in a timely manner. Pick fruit at regular intervals to prevent egg-laying opportunities. Avoid overripe fruit on plants.

• To prevent SWD populations from building, remove and dispose of leftover and infested fruit.

• Reduce the amount of alternate hosts in surrounding areas. Potential perimeter and wildland hosts for SWD may include snowberry, dogwood, Himalayan blackberry, wild rose, flowering cherry, crabapple, and others.

• Biological control: Anecdotal observations suggest that predaceous bugs (e.g., minute pirate bugs, big-eyed bugs), parasitic wasps, and lacewing larvae may be important biological control agents. Use pesticides judiciously to protect natural enemies.

5. Bordeaux 8-8-100 means 8 lb copper sulfate plus 8 lb hydrated lime in 100 gallons of water. In any bordeaux formula, the ingredients always are listed in the same order—copper sulfate, hydrated lime, then gallons of water.

Bacteria resistant to various copper formulations have been detected throughout the Willamette Valley, western Washington, and British Columbia. Resistant bacterial populations will reduce the effectiveness of copper-based products.

6. Although registered, Bravo and Aliette have not been shown to be consistently effective against ripe rot. Ziram was effective in 1998 field trials.

7. Do not use Abound or QuadrisTop or Willowood Azoxy near apple orchards, as even a minor amount of drift can be phytotoxic to certain apple cultivars. Even the minor amount left after triple rinsing can be damaging.

8. Botrytis rot strategy - Rain events dictate incidence and severity of Botrytis (including overhead irrigation that keeps fruit wet for extended periods). Use rain forecasts to guide applications during bloom and pre-harvest. Fungicides work best when used before a rain event. Alternate tank-mix fungicides from different groups or use prepackaged mixes with fungicides with different modes of action to minimize problems with resistant strains. Try not to use any one group more that twice during the growing season. Strains resistant to several different fungicide modes of action (groups 7, 9 and 17) have been found in Oregon. In the absence of testing, your historical use of any at-risk fungicide will be the best predictor of resistance.

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 can be used safely if you follow recommended precautions. Follow all label requirements; 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 (EPA), 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 (IPM) 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 non-target 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 (REI) specified on the pesticide label.

• Follow the pre-harvest interval (PHI) on the pesticide label before harvesting crops or gardens and before allowing livestock to graze fields.

Oregon Poison Center

The Oregon Health & Science University

3181 S.W. Sam Jackson Park Road

Portland, OR 97239

Phone: 1-800-222-1222

If a person has collapsed or is not breathing, dial 911.

This information is provided for educational purposes only. If you need legal [or tax] advice, please consult a qualified legal [or tax] adviser.

Trade-name products and services are mentioned as illustrations only. This does not mean that the Oregon State University Extension Service either endorses these products and services or intends to discriminate against products and services not mentioned.

Use pesticides safely!

  • Wear protective clothing and safety devices as recommended on the label. Bathe or shower after each use.
  • Read the pesticide label—even if you’ve used the pesticide before. Follow closely the instructions on the label (and any other directions you have).
  • Be cautious when you apply pesticides. Know your legal responsibility as a pesticide applicator. You may be liable for injury or damage resulting from pesticide use.

© 2018 Oregon State University.

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