Transcript Insects and Disease - Delaware Science Olympiad

INSECT AND DISEASE PESTS
IN DELAWARE’S FORESTS
ENVIROTHON
TRAINING
SYMPTOMS VS. SIGNS
•
•
Symptoms
 Changes in the
plant’s
appearance that
indicate
something is
happening. Ex:
crown dieback,
wilting, cankers.
• Signs
•  Indications of the
insect or disease
itself. Ex: frass, pitch
tubes, fungal fruiting
bodies.
THE ENVIROTHON SEVEN!
• Know these:
1. Emerald Ash Borer
2. Asian Longhorned
Beetle
3. Southern Pine Beetle
4. Gypsy Moth
5. Sirex Wood Wasp
6. Bacterial Leaf
Scorch
7. Sudden Oak Death
• For each,
know:
1. Native/non-native
2. Present in
Delaware?
3. Host species
4. Symptoms & Signs
5. Type of damage
6. Control measures
INSECTS
EMERALD ASH BORER (EAB)
Adults are bright
green and easy to
identify.
• Non-native
• Has not been found in Delaware, but present in
Maryland
• A threat to ash trees only
• Larvae create galleries in the cambium of
infested trees, girdling the trees
D-shaped exit hole,
splitting bark
Galleries
Woodpeckers
feeding
EMERALD
ASH BORER
(EAB)
Crown dieback
EMERALD ASH BORER (EAB)
• Control in our area = ERADICATION
(Remember, it has not been
detected yet in Delaware)
• Cut all ash trees in the area of new
infestations. Chip the trunks and
branches to a small size.
ASIAN LONGHORNED BEETLE
(ALB)
• From China
• Has been detected in New York, New Jersey,
not DE
• Threatens numerous types of trees,
particularly the maples.
ASIAN LONGHORNED BEETLE
(ALB)
• The beetle develops within
the xylem (wood) and then
bores its way out. Eventually
the many exit holes will
destroy the cambium and
kill the tree. The weakened
wood can also cause
structural failure (tree breaks
in half).
ASIAN LONGHORNED BEETLE
(ALB)
• Large exit holes
are conspicuous
signs of ALB
infestation.
ASIAN LONGHORNED BEETLE
(ALB)
Infested trees must be removed,
and chipped to destroy all beetles.
ASIAN LONGHORNED BEETLE (ALB)
Packing materials are inspected at ports of entry.
SOUTHERN PINE BEETLE (SPB)
• Native
• Present mainly in
southern DE
• Hosts are hard pines (all
except white pine)
• Chews galleries which
can girdle trees. Also
introduces a harmful
fungus.
• Delaware is at the
northern end of its range.
A more serious pest in
the South.
SOUTHERN PINE BEETLE (SPB)
• Infested stands can
be detected with
aerial surveys.
Infested pines
display brown
foliage.
SOUTHERN PINE BEETLE (SPB)
Pitch tube
Small round
holes
S-shaped
galleries
SOUTHERN PINE BEETLE (SPB)
Control
Infested trees can be cut and
burned, chipped, or sprayed.
GYPSY MOTH
• Non-native
• Introduced into
Massachusetts in 1869.
Since then it has spread
throughout the
northeast, including
Delaware.
GYPSY MOTH
• Larvae feed on the
leaves of many
broadleaved
species, particularly
the oaks.
• Host trees are
damaged through
defoliation.
GYPSY MOTH
• When severe defoliation occurs several years in a
row, widespread mortality can result.
GYPSY MOTH
Defoliation can be seen
from the air during June
survey flights
Egg masses
GYPSY MOTH
• Egg masses are easily seen in the fall. These methods
can determine the need for a control program the
following spring.
• Control = chemical sprays.
Sirex Wood Wasp
• Non-native
• Has not been found in Delaware
• Threatens loblolly and other pines
• Forms galleries that injure trees
• Carries a fungus that causes more damage
Sirex Wood Wasp
Symptoms / Signs
Round
exit holes
Resin
beads
Wilting and
discoloration
Sirex Wood Wasp
Control
• Control measures unknown (new pest)
• Biological controls have been successful in other parts
of the world
• Early detection surveys in DE using trap trees
Red pine trap
tree at White
Clay Creek SP
DISEASES
Bacterial Leaf Scorch (BLS)
Control:
• Native to the United States
• Present throughout Delaware
• Hosts = red oaks and other trees
• Mainly northern red, pin, black, and scarlet oaks
• Symptoms = Marginal leaf scorching in late summer
and fall, dieback
Bacterial Leaf Scorch (BLS)
• The bacteria are spread (vectored) by insects that feed
on the xylem
• Bacteria reproduce and physically clog the xylem
• Simply a “plumbing” problem. Not enough water can
move through the xylem to branches and leaves, so
living tissues dessicate and die.
Bacteria
clogging
xylem
Bacterial Leaf Scorch (BLS)
Symptoms
Marginal leaf scorch
Dieback
Bacterial Leaf Scorch (BLS)
Control
• No proven prevention
• No proven cure
• Treatment trials ongoing
in Delaware and elsewhere
• Do not plant northern red
oak or pin oak
Sudden Oak Death (SOD)
• Non-native
• Has never been found in Delaware
• Threatens oaks and other trees, as well as viburnums and other
understory plants
• Two types of symptoms:
• Understory plants
• Foliar scorching
• Twig dieback
• Overstory trees
+
• Bleeding stem cankers
• Dieback
Sudden Oak Death (SOD)
Understory plants
Overstory Trees
Twig
dieback
Bleeding
canker
Foliar
symptoms
Dieback
Sudden Oak Death (SOD)
Control:
• No control in generally infested areas such as
California
• Control in other areas is quick response after
detection. Cut, pile, and burn is an accepted
prescription in new detection areas.
• Quarantines are in place to prevent new introductions.