WSU Whatcom County Extension

Integrated Pest Management for Blueberries

Post-Harvest

Decision Making Matrices

 

Pest
Brief Description
Damage / Reason for Concern
Monitoring Approaches
Decision Points / Tolerances
Management Options
Follow Up
INSECTS

 

Aphids

Winged aphids are being produced again at this time.  Most aphid populations are being kept in check by natural predators.  

Deformation of leaves.
May cause honeydew formation and sooty mold on fruit.
May transmit viruses; Scorch virus is especially problematic.

Check 5 leaves at each plant.
Look for winged and wingless aphids as well as for aphid mummies.  Record number of leaves with over 5 aphids per leaf.

Consider treatment if in a scorch virus area and more than 10% of leaves checked have more than 5 aphids per leaf. In scorch areas, post-harvest treatment is recommended, before eggs are layed for overwintering.

Reduce excessive nitrogen use.  Aphids (and other piercing/ sucking insects) are attracted to high nitrogen tissues.

Foster habitat for beneficial insects.

Chemical control.

Continue scouting for aphid and beneficial insect populations.

Root Weevils

Obscure root weevil adults are more numerous in September and October.  They are ¼ inch long with a wavy brown line across the back towards the rear.

Feeding damage on foliage and new stem growth.
Feeding damage on roots.

Inspect leaves for notching damage.  Shake plant onto cloth or use beating tray to find adults in foliage. 

Inspect soil under plants for larval root weevils.

Consider treatment for next spring. If damage has been seen in the current season.

Beneficial nematodes can be used.  Apply in early Autumn when soil temperatures are warm and rainfall is common.

 

Tent Caterpillars and Fall Webworms

Fall webworm tents may be present until the middle of September.  Tent caterpillars will overwinter as egg masses on stems.  Egg cases appear as brown or gray foam like substance.

Defoliation of plant.
Yield reduction.

Inspect branches for overwintering egg cases.

Monitor entire field for tents of caterpillars

Rarely of economic concern.

Hand pick or prune out branches with egg masses.

Dormant oils may be applied in January and February.

Begin scouting in spring for emerging caterpillars.

DISEASES

 

Mummyberry

Inoculum for next season is as dropped fruit from this season.

Loss of yield due to infected fruit.

Scout for mummyberries fallen to the ground.

If there has been a problem with this disease, consider treatment.

Following harvest, cultivate shallowly to bury mummies.

Chemical

 

Godronia Canker

The red flag of dying leaves may be noticed if infection is present.  Bull’s eye cankers are still a good indicator.

Stem girdling when cankers get large.

During pruning, monitor for cankers and red flag leaves.

No tolerance established

Prune out infected wood.
Choose resistant varieties.

Educate pruning crew on how to identify infection and how to prune out infected wood.

Bacterial Blight

Reddish black to brown cankers may be seen.

Stem girdling, death of buds.

During pruning, monitor for cankers.

No tolerance established

Prune out infected wood.

Chemical

Educate pruning crew on how to identify infection and how to prune out infected wood.

Botrytis

Infected stems appear tan or gray; black sclerotia may be seen

Reduces fruit quality and yield.

Inspect plants for symptoms on shoot tips.

No established tolerance

Prune out infected wood and keep canopy open to encourage good air circulation.

Look for infected stems during pruning.

Vertebrate Pests

 

Voles

Small rodents tunnel through soil causing air pockets in the root zone.  They will also feed on roots

Can eat roots and girdle crowns.

Set up a monitoring station using PVC pipe and apple wedge.  Check for feeding damage on the apple wedge.

20-40% of monitoring stations are positive for feeding damage

Habitat reduction.
Rodenticide baits at bait stations.

Monitor again 2-3 weeks following treatment to evaluate efficacy.

Secondary content using h2 tag. Column 2

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Heading using the h3tag

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