Transcript Slide 1
Sarah Pickel PA IPM Program PSU 2010 Christmas Tree Short Course
Insects & Arthropods
Pests of True Firs
Pests of True Firs
1. Balsam Twig Aphid 2. Balsam Woolly Adelgid 3. Cryptomeria Scale 4. Elongate Hemlock Scale 5. Spruce Spider Mite
Grand Fir –
Abies grandis
Concolor Fir –
Abies concolor
True Fir Species
Cranston’s Christmas Tree Farm Steffen’s Conifer Nursery Oakland Tree Plantation
Canaan Fir –
Abies balsamea
var.
phanerolepis
(Fern.)
www.ChristmasTreeMan.co.uk
Fraser Fir –
Abies fraseri
Balsam Twig Aphid
Mindarus abietinus (Koch) SYMPTOMS:
• Curled, twisted
needles on current year’s growth
• Stunted needles • Black sooty mold
and presence of stinging insects
Steven Katovich, USDA Forest Service, Bugwood.org
undersides of needles are showing.
Balsam Twig Aphid
• Pale, blue-green,
soft bodied insects
• Stem mothers
eggs.
(1 ST Generation) hatch from overwintering
• Stem mothers are
largest stage, but still tiny. ~ 1-2 mm
(mm ≈ dime thickness)
Balsam Twig Aphid
TRAITS:
• Feed on plant fluids
with their piercing sucking mouthparts.
• Result of this feeding
on new growth is kinked needles.
• High-volume liquid
diet causes excretion of “honey dew.”
Helpful when scouting!
BEFORE BUD BREAK – Stem mothers give birth to live nymphs (2nd Gen.) Spray after hatch!
EARLY APRIL – Stem mothers hatch from eggs (1st Gen.) Silvery overwintering egg BUD BREAK – Nymphs enter buds and start to feed MAY / JUNE – Aphid feeding causes developing needles to curl.
MID – LATE SUMMER – Winged adults emerge (3rd Gen.) to mate and lay overwintering eggs
Balsam Twig Aphid SCOUTING TIPS:
• Within 1-2 inches of new buds, look for
silver-black overwintering eggs on underside of twigs, at base of needles.
• Stem mothers will be present in early
to mid April. Look for the shiny honey dew droplets!
Balsam Twig Aphid SCOUTING TIPS:
• Tap end of branches
over dark, flat surface.
– Treat if majority of trees
have < 2 aphids.
• Before buds open,
nymphs may hide in expanding cones.
– Consider removing
cones early if population is high.
North Carolina State University
Balsam Twig Aphid Management:
• Time to treat with registered insecticide
is after egg hatch, but NO LATER than bud swell. One spray should be sufficient.
• Spraying before bud break means
preserving insect predators, which emerge later.
Balsam Woolly Adelgid
Adelges piceae (Ratzeburg) SYMPTOMS:
• Flat top or crooked terminal • Gouting (swelling) around
buds and internodes
• Stiff, inflexible trunk and large
lateral branches
• White cottony masses on trunk
and large branches
• Dead shoots or branches (red
or brown needles)
William M. Ciesla, Forest Health Management International North Carolina Forest Service Archive
Balsam Woolly Adelgid
TRAITS:
• Round • Soft-bodied • Purplish-black • Wingless • Covered with
white wax
North Carolina Forest Service Archive
James McGraw, North Carolina State University
EARLY SPRING – Adelgids mature, develop wax and resume feeding, which causes red wood and gouting WINTER - immature Females remain dormant.
BEFORE BUD BREAK (A FEW WEEKS) – Females produce clusters of 50 – 200 eggs.
ABOUT BUD BREAK – Crawlers hatch and find a place to settle permanently and feed.
Spray after 1 st hatch!
MID-SUMMER – 2nd Gen. begins when settled crawlers mature and lay eggs. The new crawlers will become overwintering immatures.
Balsam Woolly Adelgid SCOUTING:
• Observe trunk for white wax
Photo: North Carolina State University, Scouting Fraser Fir in North Carolina (AG-573)
Balsam Woolly Adelgid MANAGEMENT:
• Make single application when 1
st
generation crawlers emerge.
• Spray needs to penetrate to trunk
of the tree!
Cryptomeria Scale
Aspidiotus cryptomeriae (Kuwana) SYMPTOMS:
• Mottled yellowing on
the tops of the needles.
• Damage to the
denser, lower and inner branches of the tree.
• Premature needle
drop.
Cryptomeria Scale
ADDITONAL HOSTS:
• Spruce • Douglas Fir • Pines (less common)
Cryptomeria Scale
TRAITS:
• Oval – round
armored scale
• Found on underside
of needles
• Whitish scale cover
and yellow cast skins visible under cover give scale a “fried egg” appearance.
Photo: United States National Collection of Scale Insects Photographs Archive, USDA Agricultural Research Service, Bugwood.org
LATE MAY / EARLY JUNE – Females lay eggs which stay under scale covering.
LATE SPRING – Scales mature into adult females and males Overwintering immature scales EARLY TO MID JUNE – Scale nymphs or crawlers hatch out of eggs and move out from under the mother’s scale cover Spray active crawlers JUNE / JULY – Crawlers settle and begin to form scale covering and feed.
EARLY AUGUST – 2 ND of eggs develop.
generation
Cryptomeria Scale
MANAGEMENT:
• Monitor undersides of lower
branches near the trunk and use a hand lens to see if crawlers are present.
• Some level of control can
come from natural predators.
• When crawlers emerge,
make 2-3 applications 7-10 days apart with a registered insecticide or super-fine horticultural oil.
Elongate Hemlock Scale
Fiorinia externa (Ferris) SYMPTOMS:
• Yellowed needles on lower
branches, beginning at trunk
• Damage moves upward as
population increases.
• Scale coverings on the underside
of the needles
• Tree may appear flocked • Premature needle drop • Eventual branch and limb
dieback and death of tree with severe infestations
Elongate Hemlock Scale
ADDITONAL HOSTS:
• Hemlock • Spruce • Douglas Fir • Pines (less common)
Elongate Hemlock Scale
LIFE CYCLE:
– Similar to Cryptomeria, but all stages
may be present at anytime through the season.
– Crawlers can be active in April as
soon as temperature warms, but are most prevalent in Late May / Early June.
Oval females produce protective “elongate” covering. Male scales mature into adult winged insects MALE FEMALE MARCH – MAY - As scales develop, male and female armor differs.
THROUGHOUT SEASON – Eggs are laid within female casing.
Spray active crawlers LATE MAY – Crawlers begin to appear and continue throughout growing season NOVEMBER - MARCH – Scale overwinters in several stages
Elongate Hemlock Scale
MANAGEMENT:
• When crawler numbers increase in Early
June, begin spray program with a registered insecticide:
– 3 applications; 1 every 4 weeks
OR
– 4 applications; 1 every 3 weeks
(This may not be necessary every season!)
Spruce Spider Mite
Oligonychus ununguis (Jacobi) SYMPTOMS:
• Yellow or bronze stippling
at base of needles
• Heaviest damage found
at bottom of tree, near trunk
• Damage may appear
most severe during hot dry weather.
• Premature needle drop. • Fine webbing on needles
and twigs. Cast skins, dead mites, dirt and other debris will be trapped in the silk.
Spruce Spider Mite
ADDITONAL HOSTS:
• Spruce • Douglas Fir • Pines (less common) • Arborvitae
Spruce Spider Mite
TRAITS:
• Tiny (1/50 inch) oval
mite
• Body covered with
setae or hairs
• Color varies from
green to dark red
• Eggs are usually tan
to bright red
• Found on twig or
needles, close to the base
Spruce Spider Mites
• Eggs will hatch at a range of 7 – 121
Growing Degree Days, usually in early to mid-April.
• There are multiple generations
throughout the growing season.
• Look for twigs showing a yellowing at
the base of the needles.
Eric Day, Virginia Polytechnic Institute and State University, Bugwood.org
Spruce Spider Mites
Two nymphal stages follow MID-APRIL – Larvae begin to hatch from eggs Overwintering eggs Within 6 days of egg hatch, adults can be found.
All stages feed on chlorophyll in needles, causing needle stippling.
Webbing develops on foliage as populations increase.
Spruce Spider Mites
MANAGEMENT:
• Monitor by tapping
branches over white paper. Consider treatment if majority of branches have 10+ mites each.
• Treat with dormant oil
before egg hatch in Early Spring (7-121 GDD).
• Apply registered miticide
or horticultural oil in spring or summer when mites are active.
For seasonal information:
Check out the PA Christmas Tree Scouting Report posted weekly from the end of March through June.
•
Online at http://ctrees.cas.psu.edu
• Also available at 1-800-PENN-IPM • Email me at
be included on the distribution list and receive the report via email.
to
Photo Credits:
• All unlabeled photos are credited to
Pennsylvania Department of Agriculture.