Transcript Insects and Disease - Delaware ENVIROTHON

Insect and Disease Pests
In Delaware’s Forests
Envirothon Training
Updated October 2007
Glenn (Dode) Gladders
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:
• For each, know:
1.
2.
1.
2.
3.
4.
5.
6.
3.
4.
5.
6.
7.
Emerald Ash Borer
Asian Longhorned
Beetle
Southern Pine Beetle
Gypsy Moth
Sirex Wood Wasp
Bacterial Leaf Scorch
Sudden Oak Death
Native/non-native
Present in Delaware?
Host species
Symptoms & Signs
Type of damage
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.