PEST
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BRIEF DESCRIPTION
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DAMAGE/REASON FOR CONCERN
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MONITORING APPROACHES
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DECISION POINTS/ TOLERANCE
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MANAGEMENT OPTIONS
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FOLLOW UP
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Spider
Mites
(Twospotted mite is the most common spider mite)
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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.
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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. |
An increasing mite population with many
eggs and few predators.
Predator mite: spider mite ratios of 1:10 indicate potential for biological
control.
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Chemical.
Keep dust on farm roads to minimum.
Use insecticides only when necessary to avoid killing mite predators.
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Fields
that have been sprayed should be sampled 5-7 days after
the application. |
Black
Vine Weevil (BVW)
(Black vine weevil is dominant)
Others: Clay colored, Obscure, and Rough Strawberry (3/8") Woods
and Strawberry (1/4") |
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 which hatch into grubs in soil and feed on
roots during fall and winter.
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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. |
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. |
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Leafrollers
(OBLR, obliquebanded is most common
in Whatcom County.)
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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.
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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.
Sprays target early developing worm stage.
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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.
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Western
Raspberry
Fruitworm
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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. |
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.
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