| Emerald Ash
Borer
Here are some links with important information about the Emerald
Ash Borer: Background Information
about Emerald Ash Borer (information obtained from aphis.usda.gov) Overview
For
several years, homeowners and landscapers in Southeast Michigan were concerned
about the loss of their ash trees to ash yellows, thinking that the
problem was due to a combination of disease, drought, pollution, acid rain, and
poor soils. The trees exhibited a top-down dieback, yellowing leaves, dense sprouting
from roots and trunks (epicormic shoots), and other signs of tree
stress typical of ash decline or other native phloem borers such as two-lined
chestnut borer. One-third to one-half of the affected ash trees branches
died within a year, and most of the canopy was dead within two years. The
Emerald Ash Borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae),
was identified as the causative agent in ash tree mortality and decline in the
Detroit metropolitan area. This beetle was unknown in North America until June
2002, when it was discovered killing ash trees in southeast Michigan and neighboring
Windsor, Ontario, Canada, located across the river from Detroit, Michigan. Before
the end of the month, the Michigan Department of Agriculture issued a quarantine
of six southeastern counties (Livingston, Macomb, Monroe, Oakland, Washtenaw and
Wayne) to prevent and control the spread of EAB. Under the quarantine, ash trees,
branches, logs, and firewood could not be moved from the affected counties. The
phase of decline in individual ash trees examined during survey activities suggests
that EAB could have been established in Michigan and Canada almost a decade ago.
APHIS worked with cooperators in the development of a cooperative strategy to
contain and ultimately eradicate EAB. Control efforts consist of removing all
host trees within a half mile radius of an infested tree, using sentinel detection
or trap trees for survey, and conducting visual surveys to delimit the area of
infestation. While the survey continued in the Lower Peninsula of Michigan,
indicating that their infestation was more wide spread than initially anticipated,
early in 2003 EAB larvae also were detected on four residential properties in
Lucas County, Ohio. Then in August, more beetles were positively identified from
the city of Hicksville in Defiance County. Subsequent infestations have also been
discovered in fourteen additional counties in Ohio. Neighboring
Indiana discovered their first EAB infestation in April 2004 in ash trees located
in a Steuben County campground, approximately 40 miles north of Fort Wayne. With
continued survey in this state, the infestation has been discovered in another
six counties. Both Indiana and Ohio are conducting state-wide surveys in 2006
to determine the extent of their EAB infestations.
On June 9, 2006, APHIS
confirmed the detection of Emerald Ash Borer in Illinois for the first time. A
homeowner in a rural subdivision near Lily Lake, about 40 miles west of Chicago
in central Kane County, discovered the beetle and alerted APHIS officials. APHIS
and Illinois Department of Agriculture (IDOA) officials immediately began delimiting
survey activities to determine the extent of the EAB infestation in Kane County.
Detection surveys are being conducted in the nine counties surrounding Kane County,
which include areas in Wisconsin. In addition, the program will conduct an inventory
of nurseries, campgrounds, and other high-priority sites, such as new residential
or recent commercial developments with ash tree landscaping. A second infestation
was detected on July 12, 2006, in the Cook County village of Wilmette by Wilmette
Village Foresters. A survey has begun to determine the extent of this infestation.
On July 21, 2006, EAB was also detected in the northwest portion of Evanston in
Cook County. These detections were made as a result of an EAB state survey that
had been intensified as a consequence of other EAB detections in the state. In
late August 2003, Emerald Ash Borer was found in Maryland at a Prince Georges
County nursery. An investigation uncovered a Michigan nursery owner had shipped
123 ash trees to southern Maryland, a violation of the Michigan quarantine. A
portion of the ash trees in Maryland were sold and sent to Virginia for planting
in that state. These trees were traced down and then removed in the hopes of preventing
infestations from developing. The owner pleaded no contest and in December
a District Court judge ordered him to pay the maximum $12,300 fine and spend 200
community service hours helping Michigan communities remove dead ash trees. Maryland
and Virginia continued to trap with sentinel trees and had no detections until
September 2006 when Maryland discovered EAB in the Brandywine area. On August
22, 2006, two larvae were recovered from ash trees located in the Clinton/Brandywine
area of southern Prince Georges County during ongoing survey and eradication
activities begun after the detection of the insect in Maryland in 2003. Virginia
examined their detection trees for the 2006 season, but found no EAB.
Over
the next several months, USDA-APHIS and Maryland officials will thoroughly investigate
the area for the presence of the pest using several survey methods, including
destructive sampling. All infested trees will be removed. Based on the results
of surveys, the program will determine whether additional trees will be removed
to prevent further pest spread. In addition to survey, regulatory, and control
activities, the program is planning an aggressive outreach and education campaign
to enlist the support and cooperation of homeowners and businesses. Encouraging
residents to report possible beetle damage in their area, as well as in preventing
the spread of this insect through the movement of regulated articles, is critical
to stopping EAB spread. This non-native pest poses an enormous threat to
our urban and rural forests. EAB kills healthy trees and is so aggressive that
ash trees may die within two or three years after they become infested with the
beetle. If it is not contained and eradicated, the impact of Emerald Ash Borer
beetle attacks on ash in North America will be similar to that of the devastation
from two fungal diseases, Chestnut Blight and Dutch Elm Disease, which destroyed
woodland and urban forests in the 20th century. Importance
of the Emerald Ash Borer Emerald ash borer is a serious pest of quarantine
significance. Larvae feed in the phloem and outer sapwood, producing galleries
that eventually girdle and kill branches as well as entire trees. This invasive
pest has had a devastating impact on communities that now face tremendous tree
removal costs associated with dead or dying ash trees that pose a public safety
threat. Ash trees are important to wildlife species because of their seed
production. Ash wood is also valued for flooring, furniture, sports equipment
(baseball bats, hockey sticks), tool handles, and numerous items requiring strong,
hard wood with less rigidity than maple. These trees are as important ecologically
in the forests of the northeastern United States and eastern Canada, as they are
economically. They are sought out for urban tree planting, partly because they
are not defoliated by the (exotic) gypsy moth. Other
repercussions include decreased property values, losses in long-term supply of
ash wood, decreased air quality, increased electricity use during hot weather,
and impacts on Native American cultures that use ash wood for traditional crafts
and ceremonies. In addition, there are other negative impacts on wildlife and
natural ecosystems. As a vital component of forest succession, ash colonizes and
stabilizes disturbed areas. Ash also is one of the few native trees able to out-compete
weeds that prevent most other species from getting established.
States
which become infested could lose billions of dollars in forest products, and quarantines
imposed by state and federal agencies may have dire consequences for plant and
wood products industries. Severe damage would also occur within the tourist industry. Exotic
organisms, like the emerald ash borer, are often more destructive in a new range
because they do not have natural population controls such as parasites, predators
or diseases. Host plants, innocent of previous contact with an organism, have
not had time to adapt and develop effective defenses against them. BiologyMating
occurs during the first 7-10 days after emergence, with females mating multiple
times. Each female lays an average of 77 eggs in bark crevices from late May through
July, and these hatch in 7 to 9 days. Larvae tunnel in the cambial layer, feeding
on the phloem and outer sapwood, and move into the sapwood as they increase in
size. Larva feed aggressively until cooler fall temperatures arrive, and then
over winter in the tree. Pupation occurs in late April to June. The pupal chamber
is constructed by tunneling into the sapwood at a shallow angle. Newly-formed
adults remain in their pupal chambers for 8-15 days, then bore through the bark
to the outside. Adults emerge in mid-May, peaking in late June and may continue
emerging as late as mid and late July. Adults prefer clear, calm days and the
warm, sunny sides of the trees and can be observed in the sunlit portions of the
crown. Adult females live approximately 22 days; whereas males live an average
of 13 days. HostsIn the United States and
Canada only ash trees (Fraxinus spp.) appear to be affected. Ash trees are widespread
in Canada and the United States. All 16 native ash species are susceptible to
EAB attack. Six native ashes are valuable commercial species, while the others
are important in communities as integral parts of urban landscape. The national
urban impact from EAB could exceed $20 billion. Healthy ash trees of any size
(from as little as 5 cm in diameter) can be affected. Chinese scientists
report that EAB can also attack trees in the genus Ulmus (elm), Juglans (walnut
and butternut), and Pterocarya (wingnut). Pterocarya species are not native to
North America but are in the same family as walnuts, pecans, and hickories (genus
Carya). One trait common to all these genera is that the wood is ring porous.
So far, only ash trees have been infested in North America, even in mixed stands
of ash and American elm. DistributionEmerald
ash borer occurs in China, Mongolia, Inner Mongolia, Korea, Japan, Taiwan and
the Russian Far East. In North America, EAB currently has infestations
in Michigan, Ohio, Indiana, Illinois, and Maryland, as well as Windsor, Ontario,
Canada. SymptomsSymptoms of the ash decline/borer
complex include: - Initial thinning or yellowing of the foliage (general
or limited to certain branches).
- Epicormic shoots may or may not
be present on declining trees.
- Woodpecker injury--woodpeckers strip
away small patches of bark, so that they can extract the borers.
- D-shaped
emergence holes, about 3 mm in diameter, are probably present in multiple year
infestations.
- Larval galleries--typical galleries meander, bending
suddenly, and are packed with frass.
Deborah McPartlan National
EAB Program Coordinator (301) 734-5356 Email: deborah.l.mcpartlan@aphis.usda.gov |