WSU Whatcom County Extension

Integrated Pest Management for Raspberries

Bloom/Pre-Harvest

Decision Making Matrices

(Late May through Early July)

PEST
BRIEF DESCRIPTION
DAMAGE/REASON FOR CONCERN
MONITORING APPROACHES
DECISION POINTS/ TOLERANCE
MANAGEMENT OPTIONS
FOLLOW UP
INSECTS

 

 

Armyworms and Cutworms

 

 

Pale green to brown larvae. More active at night.

 

Some can cause significant defoliation.
Harvest contaminants.

 

Beating tray samples.
Look for feeding damage on foliage. Cutworms are not evenly distributed across a field. Usually found in "hot spots".

 

Detection of worms prior to harvest in beating tray samples. 

 

Pre-harvest cleanup sprays can provide adequate worm control. Depends on material used.

 

Continue beating tray samples.
Ride harvesters to identify cutworms on belt.

 

Obliquebanded Leafroller
(OBLR)
(Most common in Whatcom County)

 

OBLR: adult moth is most likely stage during June. Peak adult flight usually in Late June. Moths are small (1/2" long), bell-shaped, and light brown with a darker band across wings.

 

Adults mate and lay eggs in June.
These eggs hatch into worms which web and feed on foliage and ripe fruit. Harvest contaminant.

 

Check pheromone traps weekly and record OBLR moth catch. Starting at 10 days after peak flight: Examine 20 hills per site for worm infested shoots. Check 4-5 sites per field. Record % infested hills. 

 

10% or more infested hills.
Applications target early developing worm stage.
A No/low moth count in the trap indicates a treatment may not be necessary.

 

Some pre-harvest insecticides used as cleanup sprays will control leafroller larvae if timing is accurate. 

 

Monitor during harvest period.
OBLR hatch may not occur until mid-July.

 

Orange Tortrix Leafroller
(OT)
(Most common in Western Oregon and SW Washington)

 

Adults begin emerging late April to May. Adults are gray or fawn colored with a wingspan of ¾ inch. Due to overlapping generations and successive egg hatches it is common to find eggs, larvae, pupae, and adults.

 

Adults emerging at this time lay eggs for the next generation. These eggs hatch into worms which web and feed on foliage and ripe fruit. Hatch of the first summer brood of larvae is likely to coincide with harvest and therefore contaminate fruit.

 

Check pheromone traps weekly and record OT moth catch. Starting at 10-14 days after peak flight: Examine 20 hills per site for worm infested shoots. Check 4-5 sites per field. Record % infested hills. 

 

10% or more infested hills.
Applications target early developing worm stage.
A No/low moth count in the trap indicates a treatment may not be necessary.

 

Some pre-harvest insecticides used as cleanup sprays will control leafroller larvae if timing is accurate.

 

Continue checking traps for adults and sampling % infested hills.

 

Raspberry Beetle (Fruitworm)

 

Small (1/6" long) golden brown elongate beetle.

 

Adults feed on fruit buds and flower parts. Eggs laid in flowers hatch into larvae that bore into fruit.

 

Continue beating tray samples to detect adults. Evaluate control if spray was applied. 

 

For decision making, fruitworm population should have been checked prior to bloom.

 

Optimum timing for chemical control is pre-bloom prior to egg-laying and before bees are in the field. 

 

Continue beating tray samples. 

 

Spider Mites
(Two-spotted mite is the most common spider mite)

 

Adults are about 1/50" long, have eight legs, and are light tan or greenish in color with a dark spot on each side, which looks like a saddle.

 

Feed on underside of foliage.
Reduced plant vigor, water loss and premature defoliation.

 

Examine foliage at several sites using a 10X hand lens beginning in early May. Collect 10 leaflets at each site and record the number of spider mites and mite predators found. Check every 2 weeks.

 

Thresholds are variable depending on plant vigor.
Pre-harvest guideline is an average of 10 mites/leaflet in the absence of predators, or an average of 25 mites /leaflet if predator to spider mite ratio is less than 1:10.
Predator:spider mite ratios of 1:10 indicate potential for effective biological control.

 

Chemical.
Keep dust on farm roads to minimum.
Use insecticides only when necessary to avoid killing mite predators.

 

Fields that have been sprayed should be sampled 5-7 days after the application. 

 

Spotted Wing Drosophila (SWD)

 

Adults are small flies (2-3 mm) with red eyes and a pale brown thorax and abdomen with black stripes on the abdomen. Adult males have a black spot towards the tip of each wing. Adult females have a large, saw-like ovipositor for inserting eggs into fruit.

 

This fly damages ripe and ripening fruit. Females lay 1-3 eggs per fruit by inserting their ovipositor into the fruit revealing small scares and indented soft spots and bruises on the fruit surface.
Eggs hatch and the larvae develop and feed inside the fruit, causing the flesh to collapse around the feeding site within as few as two days.

 

As soon as fruit begins to ripen place traps in fields using a 16oz plastic cup containing about ½” apple cider vinegar. Monitor traps twice per week and record number of adults found.
Also, monitor for small puncture (oviposition scar) wounds on fruit and soft fruit.

 

Thresholds are currently not available for this pest.
In most cases detection is the advised threshold.

 

This is a new pest to the Pacific Northwest; therefore, thresholds and management are not well established.

 

Continue to monitor traps and check fruit for small scares and the presence of larvae.

 

Strawberry Crown Moth (SCM is more common in the Willamette Valley and Southwest Washington)

 

Adults emerge in Late June and July, mate, and lay eggs. Adults are clear winged moths that resemble yellow jackets, with a wingspan of about 20 mm.

 

Larvae can cause economic damage in red raspberries by girdling the canes causing the plants to become stunted and have poor vigor.

 

Watch for weakened areas in the field containing brittle or collapsed canes. Signs of feeding on the outer crown and root surface may be present. Examine the crown and lower canes for signs of boring.
Place pheromone traps in the field early June and check weekly to indentify emergence.

 

No threshold is established.
Consider chemical control if signs of boring or feeding on the outer crown and root surface are visible; or if adults are found in the traps.

 

The same fall or spring insecticidal drench used to control Raspberry Crown Borer will also control SCM.

 

Continue to monitor traps for adult moths.

 

Weevil,
Black Vine
(BVW is the most commonly found species)

 

Adult black vine weevils begin emerging from the soil usually in late May. Adult beetles are 7/16" long and predominantly black. Found in foliage at night or on cool, cloudy days. They cannot fly.

 

Adults are harvest contaminant.
Adults lay numerous eggs (up to 200) which hatch into grubs in soil and feed on roots during fall and winter.

 

Take 10 beating tray samples at each of several sites in a field and record the number and type of weevils detected. Examine foliage for signs of weevil feeding - notching of leaf margins. 

 

Field history is important.
1 or 2 weevils per 10 trays indicate that a pre-harvest spray should target weevils. Young fields are likely to be cleaner.
Harvest contaminant thresholds will vary based on the end product usage and processor. Processors of IQF fruit have low tolerance for contaminants. Talk to your buyer for their threshold

 

Consider basal insecticide application to control BVW
before egg laying starts.
May precede usual timing for clean-up spray. Pre-harvest clean up spray, applied at night.

 

Resample soon after treatment with beating tray or by riding mechanical harvesters. 

DISEASES

 

 

Botrytis Fruit Rot and Cane Botrytis

 

Botrytis infection of blossoms not easily seen. Gray powdery spores form on rotting berries. Fungus resides in immature fruit as latent infection.

 

Reduces fruit quality and yield. Spores from fruit infection can infect and weaken cane tissue.

 

Examine fruit for gray mold.
Record severity on a scale of 0-3.

 

Interval between protectant fungicide applications may be lengthened if weather is dry.

 

Fungicides at 10% and full bloom. Presence of diseased fruit may indicate need for fungicides during harvest period.
Avoid overhead irrigation.

 

Examine fruit and canes during harvest.

 

Cane Blight

 

Fruiting canes are weak/brittle at catcher plate level. Disease can only enter new canes through wounds.

 

Fruit laterals may wilt and die
Infection of new canes can reduce yield in following year.

 

Inspection of fruiting canes by scraping away bark at catcher plate height to see vascular tissue.
Record % infected hills.

 

If 1-3% of canes are infected, consider treatment during or immediately after harvest.

 

Fungicide application to protect primocanes during and immediately after harvest.

 

Adjust catcher plates to minimize wounding during harvest. Avoid overhead irrigation.

 

Phytophthora Root Rot

 

Soilborne fungus which can cause root and crown rot. Infection favored by saturated soil conditions. Diseased plants have lack of feeder roots, poor vigor canes. Interior of major roots and crown are brown to black.

 

Damage seen as collapse of fruiting laterals, wilting primocanes with onset of hot weather. Reduced vigor and yield.

 

Target yellow plants with sudden wilting.
Pull samples as soon as symptoms are seen.  Send for ELISA/ PCR test.

 

There is no threshold, decision making around this pest complex is complicated.
Growers should consider these factors: age of planting, size of effected area, results of pathogen testing, variety.

 

Fall and /or spring fungicides. Consider hilling rows up in existing fields or planting new fields into pre-shaped hills.
Clean tillage equipment before moving from diseased fields to healthy fields.

 

Watch for symptoms just prior to and during harvest.

 

Spur Blight

 

Irregular-shaped brown lesions with yellow margins on fruiting lateral leaves. Brown wedge- shaped lesions on lower primocane leaves.

 

Can damage fruiting lateral foliage, weaken primocane buds and increase susceptibility to winter injury.

 

Continue to examine fruiting laterals and primocane leaves for spur blight lesions.
Record severity on a scale of 0-3.

 

Consider field disease history. Two weeks pre-bloom and early bloom period is key timing for preventative sprays.

 

Selected fungicides as applied for botrytis fruit rot.

 

Continue to monitor during harvest.

 

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