Pest threats to trees Adam Lipera Gypsy Moth Caterpillar causes - - PowerPoint PPT Presentation

Pest threats to trees

Adam Lipera

Gypsy Moth

• Caterpillar causes most of the

damage (physical)

• Affected trees: oaks, aspen, apple,

sweetgum, alder, linden, birch, poplar, willow, and hawthorn

• Last treatment: May 2008, with no

recent outbreaks

Emerald Ash Borer

• Grub causes most of the damage

(physical)

• Affected trees: ash
• Last treatment: ongoing, with

injection treatments on Champion trees and large street trees every two years

• Virginia is currently under

quarantine

Dutch Elm Disease

• Spread by elm bark beetles
• Affected trees: elm, zelkova
• First sign of infection is typically upper

branches displaying leaves starting to wither and yellow in summer, months before the normal autumnal leaf shedding

• Last treatment: ongoing, with injection

treatment of Oakland Park elm every two years

Asian Longhorned Beetle

• Grub causes most of the damage

(physical)

• Affected trees: maple, poplar, elm,

willow

• Has not been sighted in Arlington

County, however, due to the wide range of species affected, this is a high threat

Asian Longhorned Beetle

Walnut twig beetle

• Carries Thousand Canker Disease
• Affected trees: walnut
• Monitored for evidence, but no

walnuts showed signs of infection

Dogwood Anthracnose

• Fungus causes dieback or death of

infected trees

• Early symptoms begin in mid to

late May as leaf spots with tan or purple borders

• Affected trees: dogwood

Tree Scale

• Scale infestations weaken the host

tree, and if the infestation is severe enough the tree can die

• Damage includes: branches covered

with small bumps (the bumps are actually the insects), yellow or brownish leaves, premature leaf drop, twig or branch dieback, slower growth, excess secretion of sap/ honeydew

Spotted Lanternfly

• Not a fly, more of a hopper/jumper
• Feeds on woody and non-woody

plants by piercing the tissue of foliage and young stems and sucking the sap

• Host list in Virginia: tree of heaven,

cherry, locust, maple, elm, Virginia creeper, white pine, wild grape, table grape, hackberry, poison ivy, multiflora rose, mulberry, sumac, walnut, English ivy, bush honeysuckle, Japanese honeysuckle, crab apple, boxelder

• Banding and monitoring by Arlington

County to be done this year (Spring 2019)