Exotic Forest Insect Guidebook 2006
PDF (6,024kb)
Prepared by:
Troy Kimoto
Plant Health Survey Unit Canadian Food Inspection Agency
Marnie Duthie-Holt
Medi-For Forest Health Consulting
The Exotic Forest Insect Guidebook is intended to reduce the number of invasive alien species (IAS) that enter Canada.
The guidebook includes descriptions of insects, the damage they cause, the host trees they attack, and their geographic distribution. Most of the species identified in this guide could pose a serious risk to Canada's forests if introduced, but some have already been established in Canada.
This publication was originally published in 2004 by the Canadian Food Inspection Agency.
This publication is also available in hard copy and on CD. To order a copy, call 1-800-442-2342.
ACKNOWLEDGMENTS
We are very grateful to Rob Favrin, Louise Dumouchel, Bruce Gill, David
Holden, Erhard Dobesberger, John Garland and Doreen Watler, CFIA, Leland Humble, Edward Hurley
and Wayne MacKay, Canadian Forest Service, John Borden, Simon Fraser
University, Jerry Carlson, New York State Lands and Forests and Ron Kimoto for
reviewing various sections of the text. As well, preliminary text contributions
were made by Scott Holt, Medi-For Forest Health Consulting and Jennifer
Burleigh and Alex Gustafsson, Phero Tech Inc.
French translation was reviewed by Louise Dumouchel, Jean-Guy Champagne,
Steve Cote, Marcel Dawson, Mélanie Mecteau, and Jacqueline Van Acker.
Various literature searches were conducted by Patricia Madaire and Greg
Eldridge, Agriculture and Agri-Food Canada. Design review was conducted by Rob
Favrin, Jacqueline Van Acker, Kurt Sauder, Nancy Kummen, Jerry Dowding, Ches
Caister, Kara Soares and Ken Marchant, CFIA.
Financial assistance for the production of this guidebook was provided by
the Professional and Technical Development Section, CFIA.
Troy Kimoto and Marnie Duthie-Holt
Trees and forested areas are invaluable resources as they provide
ecological, economic, spiritual and social benefits to all within Canada.
Human activities impact the surrounding environment by altering the
structure and dynamics of ecosystems. The rate and extent of global trade and
human migration have increased dramatically over the years. This expansion has
increased the probability that organisms can be accidentally moved to and
become established in areas outside of their natural range.
Most organisms fail to survive when introduced into a new environment or
moved over long distances. Sometimes the conditions are suitable for an
introduced organism to survive, find an appropriate food source and
successfully reproduce in its new environment. Once established, their
population levels may increase rapidly because the predators, parasites and
diseases which attack them in their native range are not usually present in the
new environment.
Canadian forests have been dynamically evolving since the last ice age (~10,
000 years ago) in response to fire, climate and indigenous insects and
diseases. When exotic forest pests become established, trees are abruptly
exposed to a new invasive species and may not have the mechanisms to defend
themselves. In conjunction with the absence of population-limiting factors, the
establishment of introduced forest pests may lead to either localized or large
scale tree mortality that can impact private residences, municipalities,
industries and forest ecosystems. Recently, the Emerald Ash Borer (Agrilus
planipennis), a metallic woodborer native to China, has become established in
North America where it is causing extensive mortality to green and white ash
trees and threatens to severely limit the distribution of these species.
However, in this insects native range such damage has rarely been
observed.
The Canadian Food Inspection Agency (CFIA) has a mandate, under the
federal Plant Protection Act, to protect Canadas plant resource base
against the introduction and spread of quarantine pests according to standards
outlined in the International Plant Protection Convention. The CFIA does this by developing
import, export and domestic regulatory policies and associated inspection,
surveillance and eradication programs.
PATHWAYS OF INTRODUCTION
In terms of introduced organisms, pathways can be defined as means by which
organisms are moved to new environments. Various plant health policies have
identified that the greatest risks of introducing forest insects are generally
associated with the importation and domestic movement of:
- Wood packaging material
- Shipping containers
- Nursery stock
- Firewood
- Raw logs with bark
- Christmas trees
- Personal effects
Wood packaging material can be one of the most important pathways for the
introduction of exotic forest insects because it is often used to ship a wide
variety of consignments (e.g. steel products,
granite, break bulk, glass, machinery, vehicles, consumer products, etc.).
The risk posed by wood packaging varies with wood quality and degree of
finishing. The higher the grade and degree of finishing, the less likely the
possibility of infestation.
In the past, many exotic plant pests have been intercepted on loose wood
dunnage, pallets, crating or other wood packaging made from low grade material
from various origins. North America has recently agreed to begin the
implementation of a new International Plant Protection Convention standard
(ISPM #15) that
will regulate the movement of international wood packaging.
Cities and urbanized areas have higher probabilities of receiving exotic
forest pests because of the large volume of goods that are imported into those
areas. Urban trees and forested areas are often exposed to poor growing
conditions due to soil compaction, air pollution, mechanical damage, etc. The combination of these factors increases their
vulnerability to exotic forest pests.
CFIA forest pest
surveillance programs target the routes of these pathways and high risk
locations (e.g. international ports or
terminals, industrial zones, landfills and storage sites, nurseries, etc.). For example, high risk consignments within
transport containers are inspected at major ports before they are permitted to
enter Canada. However, only a small proportion of these containers are
inspected upon entry and therefore, a large volume of uninspected wood
packaging material is transported to urban and rural centres throughout Canada.
As it is a tremendous undertaking to monitor the introduction of forest pests
in a country the size of Canada, it is important to have many additional
eyes that are on the lookout for exotic organisms.
OBJECTIVES
This book is designed for public and private sector Canadians who work in
the areas of tree health and arboriculture. This book focuses more on insect
descriptions, host tree preferences, damage symptoms and geographic
distribution rather than insect biology in order to increase the probability of
finding exotic pests during tree health assessments. A key issue in the
eradication of quarantine insects is discovering and identifying populations
while they are still at low and controllable levels. Hopefully this book will
serve as an early detection tool.
This book is intended to help detect exotic forest insects and should be
used in conjunction with indigenous pest field guides. However, the information
within this book will not transform the reader into an expert
in insect identification. Some exotic insects, especially bark beetles, may
resemble indigenous or naturalized insects. Some of the damage caused by exotic
and indigenous forest insects may also be very similar (e.g. red needles). Therefore, suspect specimens need to be
examined by professional entomologists for conclusive identification. Most of
the insects included in this book could pose a serious threat if they became
established in Canada. However, there are a few that have already become
established and are being eradicated and/or regulated. The insects within this
book do not represent a complete list of exotic forest insects which could
invade Canada. There are a large number of non-indigenous insects throughout
temperate forest regions in the world and only a very small portion of these
has been included.
HOW TO USE THIS BOOK
BOOK FORMAT
Descriptions of insects in this book are organized by guilds, which
represents similarities in their biology and the part of a tree in which they
breed. Bark beetles are small insects that usually feed beneath the bark on
phloem. Woodborers are a diverse assemblage of round and flatheaded wood
borers, wood wasps, weevils and other insects that feed within the wood.
Defoliators are primarily moths, the larvae of which feed on foliage or
needles. Within this guidebook, these guilds are colour coded for convenient
referencing. The insects are also arranged alphabetically within each guild and
each family.
For many exotic insects scientific information may be difficult to obtain.
Some insects have not been extensively studied in their native range. Therefore,
there is some variation in the amount of information presented for each
insect.
For each insect, information is arranged into 6 categories:
- Identification
- Host trees
- Location of infestation within the tree
- Host condition
- Distribution
- Signs and symptoms
Identification briefly describes some of the key anatomical
features that distinguish one insect from another.
Host trees indicates which trees, by genus, are known hosts
of an insect.
Location of infestation within the tree describes the parts
(roots, root collar, bole, branches, etc.) and
tissues (foliage, phloem, sapwood, heartwood, etc.) that are attacked by the various life stages of the
insect.
Host condition outlines the health status, age and size of
trees that are attacked.
Distribution lists the countries or regions in which the
insect is either native or has been introduced.
Signs and symptoms describes the characteristics that are
indicative of insect attack (signs such as colour of frass, exit hole size and
shape, egg gallery shape, etc.) and outlines a
trees response to attack by the insect (symptoms such as resinosis,
fading foliage, thinning crown, etc.).
Literature cited within the text of this book is assigned a unique number.
Citations can be looked up in the Reference section at the back of the
book.
Two cross-reference indexes are provided. The first index can help determine
which insects will attack specific parts of a given tree. The second index
indicates which tree genera are known hosts of specific insects.
Wherever possible, non-scientific language is used throughout this book to
describe the insects. However, in some instances entomological terminology is
used. A glossary is located at the end of the guidebook to define these
terms.
DETECTING EXOTIC FOREST INSECTS
Detecting newly introduced forest insects can be very difficult because the
population may be localized and still at very low densities. Furthermore, the
signs and symptoms may be masked by other factors. However, there are specific
clues that can be used to increase the likelihood of detection. General
symptoms of decline in coniferous trees are a thin crown, stunted leader (i.e. top) and a chlorotic or reddening crown. In
broad-leaved trees, epicormic shoots, wilted leaves, thin crown and pre-mature
foliage colour change are common indications of decline. Although these
symptoms characterize many other types of forest health stress factors (e.g. drought, root disease, hail damage, insects,
mammals, salt damage, sun scald), they are also the most obvious external
indicators of exotic insects. How to Use this Book
Obtaining a search image for these symptoms is an initial step
in locating potentially infested trees. As many exotic forest insects tend to
breed in stressed trees, it is important that inspectors and surveyors check
all obviously declining trees. This is particularly important in urban areas
where trees often grow in sub-optimal conditions and are subjected to many
stress factors.
In order to find infested trees, the surveyor must scan the entire length of
a tree. Vigilance and general observation for declining trees is most
beneficial. Scanning trees while walking through parks, sparsely treed
industrial areas, woodlots, fencerows, riparian corridors or other wooded areas
is critical in quickly locating and identifying an early attack.
General symptoms of decline should draw attention to a tree or a group of
trees. The next step is to determine the causal agent. Familiarity with
indigenous or naturalized biotic and abiotic forest health factors as well as
local site conditions will greatly enhance the likelihood of an accurate
assessment. External signs of insect activity include the presence of larvae or
adults, frass (within bark cracks or crevices, on understory leaves, at the
base of the tree, etc.), exit holes, entrance
holes, pitch tubes along the bole, resinosis, gouting, oviposition niches,
defoliation (partial or complete) and silk webbing. Internal signs such as egg
and larval galleries, tunnels within twigs or branches, pupal chambers and the
presence of various insect life stages can be uncovered by removing portions of
the outer and inner bark with an axe or knife. Permission from the landowner is
always required for more invasive investigations.
If the cause of tree decline seems suspicious, contact your local municipal
or city forester, provincial ministry of natural resources
entomologist/pathologist or professional arborist. Record pertinent information
(street address or geographical coordinates, tree species affected, observable
signs and symptoms, etc.) and if possible,
collect a specimen (preferably adults) as these will assist professionals in
evaluating the situation.
SAMPLE SPECIMEN SUBMISSION
This guidebook should assist in recognizing the presence of introduced
forest insects but it can not replace the years of specialized training
required to correctly identify insect species. There are many anatomical
characteristics that require microscopic examination by specialists. The
Identification section within the text of this guidebook only
provides a general description of an insect and does not contain enough
information to allow the reader to dependably identify an insect to the species
level. If all other sources (e.g. local forest
health specialists, native forest insect guidebooks, etc.) are unable to provide a definitive identification of a
forest pest, please contact a Plant Health specialist at your local Canadian Food Inspection Agency
office(www.inspection.gc.ca).
Troy Kimoto
Survey Biologist
Canadian Food Inspection Agency
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