WSU Whatcom County Extension

Integrated Pest Management for Raspberries

Bloom/Pre-Harvest

Biology and Monitoring

(Late May through Early July)

Insects
Diseases
Vertebrates

     • Armyworms and Cutworms
     • Obliquebanded Leafroller
     • Orange Tortrix Leafroller
     • Raspberry Beetle (Fruitworm)
     • Spider Mites
     • Spotted Wing Drosophila
     • Strawberry Crown Moth
     • Weevil
 

     • Botrytis Fruit Rot
     • Spur Blight
     • Yellow Rust

     • Voles

 

Biology

Insects

Armyworms and Cutworms

A variety of caterpillars which feed on foliage can be present during mid-summer. Their feeding does not usually cause significant damage to plants, but they can be serious harvest contaminants. Most of these are nocturnal and they are very difficult to detect within a thick raspberry canopy. Often, growers are not aware of their presence until harvesting begins.

 

Obliquebanded Leafroller (OBLR)

Most OBLR are now in the late larval or pupal stages, preparing for their metamorphosis into adult moths which start flying in June. OBLR moth flight doesn't usually start until late May, with peak catch occurring in late June and early July. The larval stage of this insect is the dominant stage found during April and May.

 

Orange Tortrix Leafroller (OT)

Adults begin emerging late April to May and lay eggs in flat masses on canes and on the lower surface of leaves. This next generation will potentially coincide with harvest and therefore contaminate fruit. Due to overlapping generations and successive egg hatches it is common to find eggs, larvae, pupae, and adults. Thus, it is important to continue monitoring pheromone traps to determine when peak flight occurs.

 

Raspberry Beetle (Fruitworm)

Adult, egg and larval stages of this insect may all be present during this period, particularly if beetles were present and were not treated prior to bloom. Adult beetles feed on the flower parts and young larvae feed on the receptacle of developing fruits. Larvae can contaminate harvested fruit, but are very difficult to control as they feed within the berries. Control at this time is complicated due to presence of honeybees and multiple stages of the insect.

 

Spider Mites

Spider mites can begin to increase at this time of the year but varies from one field to the next. They are more commonly found on older or mid-shoot leaves on fruiting canes, rather than on primocanes during the early summer. White speckling or stippling of the upper leaf surface is a sign that mites are present and feeding.

There are no scientifically determined treatment thresholds for spider mites early in the season. Factors which influence treatment decisions include; spider mite density, abundance of predators, population trends, damage to foliage, weather conditions, and miticide pre-harvest interval (PHI). Spider mite increase is favored by hot, dry dusty conditions.

 

Spotted Wing Drosophila

SWD is a “vinegar fly” but unlike other vinegar flies, which attack rotting fruit, this fly damages ripening and decaying fruit. Although weather dependent, the flies can be active beginning in April. There may be as many as 10 life cycles in a season with a single life cycle lasting eight to fourteen days. Females typically will insert their ovipositor into the fruit; lay one to three eggs per fruit, 7–16 eggs per day, and more than 300 eggs in their lifetime. Pupation can take place both inside and outside of fruit. The fly thrives at cooler temperatures (68˚F), while decreasing in activity, egg laying and longevity at higher temperatures (above 86˚F). Adults are small flies (2-3 mm) with red eyes and a pale brown thorax and abdomen with black stripes on the abdomen. The most distinguishable trait of the adult is that the males have a black spot towards the tip of each wing.

 

Strawberry Crown Moth

Adults emerge in Late June and July, mate, and lay eggs on dead leaves or green leaves around the base of the plant. Adults are clear winged moths that resemble yellow jackets, with a wingspan of about ¾ inch. The forewings are nearly opaque with the edges dark bronze to almost black. The hindwings are transparent with dark veins and dark fringe. The abdomen is black, and banded with yellow on the second, fifth, and sixth segments.

 

Weevil

Root weevil larvae feed on roots and can cause damage to roots. Adult weevils feed on foliage and new stems to cause notching of new growth.

Adult black vine weevils, clay colored weevils, and strawberry weevils will be emerging during this period. When weevils first emerge, their bodies have not fully hardened and are quite soft to the touch.

Black vine weevils are up to 1/3 inch long and are black with a few small yellow or orange spots. Clay colored weevils are slightly smaller than black vine weevils and are mottled with darker and lighter shades of brown or gray. Strawberry weevils are 1/5 inch long and range from black to brown in color. Other weevil species are present as larvae during this period and may be found in the soil below the plant.

 

Diseases

Botrytis Fruit Rot

Initial infection of fruit begins during early bloom when spores are dispersed by wind and splashing water to infect developing flower parts. These early infections remain inactive (latent) until fruit develops and conditions are favorable for the fungus to further infect the fruit, causing gray mold on infected berries. Mold releases spores which cause additional fruit and cane infections.

 

Spur Blight

Primocanes are commonly affected by this fungal disease which overwinters on canes infected the year before. Spores released from lesions on these canes can infect floricane and primocane foliage, usually appearing as a brown, wedge-shaped lesion. This symptom may be seen at this time of the season. The fungus then moves through the leaf and petiole and is most apparent as a purplish/brown lesion around the bud on the lower portion of primocanes. This symptom on primocanes may not be seen until mid-harvest.

 

Yellow Rust

Leaf infections in spring and early summer appear as yellowish spots on the upper leaf surface. Initially these spots are very small, but as the disease develops, additional spores (aecia) are produced in a ring around the initial infection. By summer, another yellow spore stage (uredinia) appears on the lower leaf surface as the disease cycle continues.

 

Vertebrates

Voles

Voles resemble house mice; they are 6-9 inches long, and gray or brown in color. They create tunnels in the soil and feed on plant roots and foliage near the ground. Their gnawing and chewing can girdle roots, crowns, canes and may lead to cane loss. Their tunneling creates air pockets in the root zone, which may further impact plant development.

 

Monitoring

(Mid-May) (June)

Follow general guidelines in the “Introduction” section. For each pest below, record pest numbers or symptoms on record sheet.

 

Beating Tray Sampling Method - Pest and Beneficial Insects

  • Use beating tray to survey the canopy for several insect pests that can directly damage fruit or may pose problems as harvest contaminants.
  • Visit several sites in each field.
  • At each site, take ten tray samples and record the total number of insects dislodged from foliage.
  • Hold tray about one foot below trellis wire within canopy and shake foliage by grasping wire with hand and shaking, or striking top wire three times with rubber sprayer hose to dislodge insects.
  • Alternate samples between rows and check about every ten feet down the row.

    The following insects are typically found using the beating tray method:

    Pests
         - Black vine weevils*
         - Other adult root weevils
         - Fruitworm beetles*
         - Leafrollers*
         - Miscellaneous worms*

    Beneficials
         - Minute pirate bugs
         - Lady beetles
         - Stethorus beetles*

    Incidental Insects
         - Raspberry sawfly
         - Earwigs
         - Stinkbugs
         - Lygus bugs

    *These are the most important insects which should be recorded.

 

Mid-May

Insects

Obliquebanded Leafroller (OBLR)

  • Record number and approximate size of leafroller larvae when found on beating trays.
  • Place obliquebanded leafroller (OBLR) pheromone traps out in the field in mid-May. They are a useful tool for determining peak adult activity and can help determine key periods to monitor for the second generation caterpillar stage which can be a harvest contaminant. Trap catch cannot be used to accurately reflect OBLR population size or expected damage from this insect.
    • Hang traps from the top trellis wire near canopy height within ten feet of the windward edge of a field. One or two traps in a field can provide meaningful pest management information. Check pheromone traps weekly starting in late May and throughout June.
  • Select 20 hills/plants at each site and examine shoot tips for presence of caterpillars. Examine a maximum of 5 shoot tips/hill to determine if the hill is infested. Once an infested shoot tip is found, do not examine any more shoot tips at that hill, and record that hill as infested. If you examine five shoot tips without finding any caterpillars, record that hill as clean. Record the number of infested hills for each site that you sample.
  • If 10% or more hills are infested, then a treatment may be advisable to control the overwintering spring generation prior to bloom.
  • Treatments directed at the worm stage in late May are probably too late to control any significant percentage of the larval population.

 

Orange Tortrix Leafroller (OT)

  • Record number and approximate size of leafrollers found on beating trays.
  • Monitor pheromone traps weekly to determine peak flight activity in order to predict the onset of a second generation which may become a harvest contaminant.
  • Monitor caterpillars as described for OBLR.

 

Raspberry Beetle (Fruitworm)

  • Continue monitoring raspberry beetles.
  • Optimum timing for control is prior to bloom, but controls may be justified if beetles persist.
  • The beating tray is a good tool for dislodging them from foliage.
  • Some level of control is achieved by pre-harvest clean up sprays.
  • Continue checking Rebell® Bianco white sticky traps to evaluate treatment efficacy.

 

Spider Mites

  • Examine leaves using a 10X hand lens for presence of mites and mite predators.
  • Collect ten leaflets per scouting site distributed throughout a field.
  • Count the number of spider mites and mite predators and record information at each site.
  • Mite populations can increase rapidly.
  • The following should be recorded:
    • Two Spotted Spider Mite (TSSM) adults
    • TSSM eggs
    • Yellow Mite adults
    • Predatory mites and eggs
    • Stethorus adult
    • Minute pirate bug

 

Strawberry Crown Moth

  • Watch for weakened areas within the field containing brittle or collapsed canes.
  • Examine the crown and lower canes for signs of boring.

 

Weevil

  • Expect to start seeing adult weevils in beating tray samples late in May. Record number of adults in beating tray.
  • The numbers will likely increase significantly by the middle to latter part of June.

 

Diseases

Spur Blight

  • Check floricane and primocane foliage for brown wedge-shaped lesions and record severity on a scale of 0-3 at each site scouted.
  • Most fungicides that control botrytis will also help to control spur blight.

 

Yellow Rust

  • As you are collecting leaves for mite sampling, note how many are infected with yellow rust aecia and the degree of infection. Both aecia and uredinia stages may be present at this time.
  • Record severity on a scale of 0-3 for aecia and uredinia separately.
  • A fungicide may be necessary to protect new growth if the disease is found at most sites in a field and wet weather persists. The preferred timing is to apply a fungicide prior to the presence of the summer uredinia stage, usually late April to early May.

 

Vertebrates

Voles

  • Look for tunnel entrance holes about one inch in diameter, surface runways through grass, droppings and/or chewing marks on canes and roots.
  • Monitor for voles using monitoring stations with apple baits, and record percent of stations positive for feeding damage.
  • Treatment Threshold - management is needed when 40% of the bait stations show positive feeding damage after 24 hours. Monitor again 2-3 weeks following treatment to determine efficacy.

June

This is a critical period for insect and spider mite monitoring because results from sampling will help determine specific pre-harvest spray needs and timing.

Insects

Harvest Contaminants

  • Continue beating tray samples to monitor weevils and miscellaneous cutworms. Record number of pests and beneficial insects found at each site.
  • Weevil counts tend to increase in mid to late June as more adults emerge from the soil. The best time of day to use a beating tray is early in the morning before weevils move down from the canopy or on cool, cloudy days when they are more likely to remain in the canopy. If you are sampling with a beating tray primarily to measure weevil activity, sampling at night when weevils are most active.
  • Take extra samples near field borders, particularly if field is adjacent to a known weevil source such as a woodlot, older strawberry field or rhododendron planting.
  • If you find just a few weevils at each site, treatment is probably warranted.
  • Where weevils require treatment, attempt to time sprays three to four weeks after peak emergence which is before most egg laying occurs.
  • If there is no feeding damage and weevils are not detected using beating trays, a specific weevil spray may not be necessary. This may allow you to use a "softer" clean-up spray which may not destroy as many mite predators.
  • Pay close attention to miscellaneous cutworm larvae at this time as well. A few small worms occasionally detected in a field may indicate a major hatch is occurring.

 

Obliquebanded Leafroller (OBLR)

  • Check leafroller traps weekly and record the catch. At about ten days after peak trap catch, it is time to monitor caterpillars in the field.
  • Examine a maximum of five shoot tips per hill from 20 hills per scouting site.
  • Record the total number of infested hills and divide by the total number of hills inspected. Multiply this number by 100 to give the percentage of leafroller infested hills.
  • If 10% or more are infested, a treatment may be necessary. Detection of leafroller larvae at most sites indicates pre-bloom insecticide application may be necessary.

 

Orange Tortrix Leafroller (OT)

  • Monitor pheromone traps weekly to determine peak flight activity in order to predict the onset of a second generation of larvae which may become a harvest contaminant. Larvae tend to appear about ten to fourteen days after peak trap catch occurs.
  • Monitor caterpillars in the field as described in the pre-bloom section.
  • Examine a maximum of five shoot tips per hill from 20 hills per scouting site. Record the total number of infested hills and divide by the total number of hills inspected. Multiply this number by 100 to determine the percentage of leafroller infested hills.
  • If 10% or more are infested, a treatment may be necessary. Detection of leafroller larvae at most sites indicates pre-bloom insecticide application may be necessary.

 

Spider Mites

  • Continue sampling leaves for spider mites and their predators at least every two weeks.
  • Compare counts of both spider mites and mite predators to earlier sampling results.
  • Trends in populations are very important when determining if treatment is necessary.
  • Revisit sites where mites were detected at the previous visit.
  • A spider mite spray may be necessary before harvest if:
    • spider mites are approaching ten/leaflet or more and there are few or no predators;
    • spider mites are increasing and there are numerous eggs as well;
    • spider mites are increasing and predator:prey ratio is less than 1:10;
    • miticide PHI is three or more days and population is building.
  • A spray decision can be delayed if:
    • available miticide has a short PHI (one to two days), allowing for treatment during harvest if it becomes necessary.
    • spider mites are difficult to find

 

Spotted Wing Drosophila

  • As soon as fruit begins to ripen place traps in fields using a 16oz plastic cup containing about ½” apple cider vinegar.
  • Monitor traps once or twice per week and record number of adults found. Also monitor for small puncture (oviposition scar) wounds on fruit and soft fruit. Adults are attracted to ripe or ripening fruit.
  • Record the number of adults found per trap and the percentage of contaminated fruit.
  • Thresholds have not yet been determined; few adults detected warrants treatment.

 

Strawberry Crown Moth

  • Place pheromone traps in the field by early June and check weekly to monitor for emergence.
  • Hang one to two traps (depending on field size) on the lower wire of the trellis (SCM are low fliers).
  • Watch for weakened areas within the field containing brittle or collapsed canes.
  • Examine the crown and lower canes for signs of boring.

 

Diseases

Botrytis Fruit Rot

  • Green and ripening fruit can show symptoms of purplish-grey, hard berries.
  • Record severity on a scale of 0-3.
  • Depending on weather conditions, a third and possibly fourth fungicide application may be necessary. The frequency of fungicide applications targeting Botrytis is greatest in fields destined for high-end quality markets, which have a very low tolerance for diseased fruit.
  • If multiple fungicide applications are made, alternate between fungicide classes to avoid resistance problems. Don’t tank mix fungicides with similar modes of action.

 

Spur Blight

  • Check floricane and primocane foliage for brown wedge-shaped lesions and record severity on a scale of 0-3 at each site scouted.
  • Most fungicides that control botrytis will also help to control spur blight.

 

Yellow Rust

  • As you are collecting leaves for mite sampling, note how many are infected with yellow rust aecia and the degree of infection. Both aecia and uredinia stages may be present at this time.
  • Record severity on a scale of 0-3 for aecia and uredinia separately.
  • A fungicide may be necessary to protect new growth, if disease is found at most sites in a field.

 

Secondary content using h2 tag.

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Heading using the h3 tag

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

WSU Whatcom County Extension 1000 N. Forest St., Suite 201, Bellingham, WA 98225 (360) 778-5800 whatcom@wsu.edu