HomeMy WebLinkAboutWD-19-89 TOWN OF NEWCASTLE
REPORT
File #
Res.
4 _A4=, #
-- - By-Law
MEETING: GENERAL PURPOSE AND ADMINISTRATION MEETING
DATE: JANUARY 23, 1989
PBUT #: wD-19-89 FILE #:
a8JECT: CORRESPONDENCE RECEIVED FROM MRS. HAZEL CRAGO
NEWCASTLE HORTICULTURAL SOCIETY:
TENT CATERPILLARS
RECOMMENDATIONS:
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It is respectfully recommended that the General Purpose and
Administration Committee recommend to Council the following:
1. THAT Report WD-19-89 be received; and
2. THAT no action be taken to control the tent caterpillars infestation
in the Town; and
3. THAT a co py of this report be forwarded to Mrs. Hazel Crago, Newcastle
Horticultural Society, P.O. Box 371, Newcastle, Ontario, LOA 1HO; and
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4. THAT Mrs. Hazel Crago be advised of Council's decision.
REPORT
1.0 ATTACHMENTS
No.1: Letter dated August 25, 1988 from Mrs. Hazel Crago,
Newcastle Horticultural Society
N0.2: Survey bulletin, Forest Insect and Disease Conditions
in Ontario, Government of Canada, Forestry Service
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WD-19-89
2.0 BACKGROUND
2.1 At a meeting held on September 12, 1988, Council considered correspondence
received from Hazel Crago, dated August 25, 1988 regarding the removal
of tent caterpillars from trees and passed the following resolution:
"THAT the communication dated August 25, 1988, from Mrs. Hazel Crago,
Newcastle Horticultural Society, requestiang the removal of tent
caterpillars from trees in the Town of Newcastle be received;
AND THAT the correspondence be referred to the Director of Public
Works for review and report to the General Purpose and Administration
Committee;
AND FURTHER THAT Mrs. Hazel Crago be advised of Council's decision."
3.0 REVIEW AND COMMENT
3.1 In 1988, there was a significant infestation of tent caterpillars on
trees in the Town. In order to respond to the correspondence received
from Mrs. Hazel Crago and phone calls from others concerning the
infestation of trees by tent caterpillars, we contacted Mr. Sida Kim,
Ministry of Natural Resourses for information concerning the problem.
Mr. Kim gave the following advice:
3.1.1 The Ministry of Natural Resourses predicts that the infestation of
tent caterpillars will be worse in 1989 than it was 1988.
However, due to an increase in natural pests, the population will
collapse in 1990.
3.1.2 Tent caterpillar infestations occur on a ten year cycle on the average
and therefore the Ministry does not take any action to control the
problem.
3.1.3 A tree service could provide the necessary sprays and the Ministry's
surveys indicate a cost of $40 to $60 per acre to spray.
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WD-19-89
3.2 Mr. Kim also sent a copy of a survey bulletin published by the Canadian
Forestry Service, Government of Canada (see Attachment No.2) . The
following points should be noted and I quote:
3.2.1 "However, a loss of leaves does not mean that the trees are dead. Trees
that have lost their foliage to the caterpillars will produce a second,
less dense set of leaves in five or six weeks. Although the insect
rarely kills healthy trees, it may weaken them, making them more
susceptible to other pests and of course reducing their annual growth
of wood. Damage to the foliage of sugar maples can reduce the sugar content
of sap the following spring, especially if an infestation persists for
several consective years."
3.2.2 "Sometimes early recognition of a potential forest tent caterpillar problem
will permit planning to avoid activities at trouble spots when caterpillars
reach their peak. They are not likely to be a serious nuisance for more
than a week. This week will coincide with the time they run out of food
on the original host trees and begin to migrate en masse, most likely
during the last week of May or the first three weeks of June. The first
signs of cocoon spinning indicate that wandering will soon cease since
most caterpillars spin their cocoons and disappear at much the same time."
3.2.3 "The forest tent caterpillar is a native pest, here for only a short time
until natural controls can bring the population back to normal levels."
4.0 SUMMARY
4.1 On the average, tent caterpillars occur in ten year cycles.
4.2 Tent caterpillars rarely kill a healthy tree,
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WD-19-89
4.3 Spraying of trees to control tent caterpillars costs $40 to $60 per acre.
Therefore, a spraying program in the Town would be very costly.
4.4 Tent caterpillars are not usually a serious nuisance for more than a week.
4.5 Populations of tent caterpillars collapse in two to three years due to
natural controls.
5.0 RECOMMENDATIONS
5.1 It is, therefore, recommended that no action be taken to control the
tent caterpillars population in the Town of Newcastle.
Respectfully submitted, Recommended for presentation
to the Committee,
/V
Walter A. Evans, P. Eng., Lawrence E. K seff,
Tative officer.
I t
Director of Public Works. Chief AdminIs's
:llv
January 9, 1898
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TYPED AS WRITTEN
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August 25, 1988
Newcastle Horticultural Society
P.O. Box 371
Newcastle, Ontario
Mayor John Winters
Bowmanville, Ontario
Dear Sir:
The Society has asked that I write to your requesting the removal of tent
caterpillars on trees in our village and possibly the whole Town!
In the August 24th edition of the Canadian Statesman we read the
Department of Works is planning to plant new trees in the Town of Newcastle
boulevards. We heartily agree with this decision. But, we feel that
existing trees should be tended. Therefore, we suggest cutting out the
tent caterpillar infestations and burning them.
Thank you
Yours sincerely
Mrs. Hazel Crago
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ATTACHMENT NO. 1
WD-19-89
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ANOTHER OUTBREAK OF FOREST TENT CATERPILLARS
People in widely scattered parts of Ontario are occasionally
pestered during the early summer by hordes ofxhungry forest tent
caterpillars crawling -from stands of denuded broadleaf trees and
wandering in search .of -food. The first known outbreak recorded
in Ontario was described by Paul Kane in 1834: "It was a
remarkable fact that the trees on each side of the river, and
part of the Lake of the Woods, for full 150 miles of our route,
were literally stripped of foliage by myriads of caterpillars,
which had left- nothing but the bare branches, and I was informed
that the scourge extended to more than twice that distance, the
whole country wearing the dreary aspect of winter at the
commencement of summer. " In the years following 'Kane's report
some eruptions probably went unrecorded, but since 1868 .there has
been an outbreak somewhere in Ontario every 10 years, on the
average.
The Forest Insect and Disease Survey (FIDS) Unit at the Canadian
Forestry Service's Great Lakes Forestry Centre in Sault Ste.
Marie maps the size and -severity of these outbreaks, and by
determining the nuznber. of overwintering egg masses on host trees
forecasts the spread4of infestations. .,, The most recent
defoliation map produced by the `FIDS Unit, along with other
relevant material is attached at the end of the leaflet. If the
map is missing, or you require further information not contained
in this booklet, contact your nearest Ministry, of Natural
Resources District Office..
LIFE HISTORY AND HABITS
Eggs are laid by female moths in bands around '.-branch tips that
are less than 13 mm (1/2 in. ) in diameter. A' ter the developing
caterpillars are fully formed inside the eggs,_ they enter
diapause and overwinter. The hatching of egg usually coincides
with initial bud development on trees in earlyspring and the
tiny caterpillars feed openly in colonies on the unfolding
leaves. These tent caterpillars do not form cAstinct silken
tents. They grow gradually larger as they feed . on developing
► Afro ti;iJ Ti;;FJN
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Note e Return t
PU41 lC WOPKS
ovestipafe and Reeorr
a DEPT: � �
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Take AppOpriate'lctia
foliage and by the time they reach a length of about 35 mm (1.5
in.) their final body colour and pattern become evident. They
are gray blue with a broad blue band along each side and a row of
keyhole-shaped white markings along the back. After 6 to
of feeding and four accompanying molts, caterpillars reach$aweeks
length of 50 mm (2 in. ) -. Soon they spin cocoons of silk among
unconsumed leaves, or almost anywhere if leaves are absent. The
pupa is formed within the cocoon and about two weeks later buff-.
coloured moths emerge. Following mating, the females each lay a
band of some 150 eggs which encircle the twig.
covered with a dark foam-like substance. Egg-laden These bands are
been known to disperse to adjacent areas where neinfestations
subsequently appeared. On warm evenings after dark, moths may be
attracted to the artificial lighting of built-up areas.
HOST TREES AND IMPACT.
Selection of the host tree on which young caterpillars will be in
to feed is made by the female moth when she lays her e g
northern Ontario, trembling aspen and oak are preferredgwhereas
in southern Ontario, sugar maple and oak are the most common
trees selected. During epidemics, after the foliage of primary .
host trees is completely consumed, caterpillars feed on various
other broad-leaf trees and shrubs, thereby completely denuding
forests of green leaves. White birch,, for instance, is sel.dom .if.
ever chosen by the moth for laying eggs and hence is not included' ;
in the list of primary host trees, yet frequently it is . stripped
of leaves where it is growing in mixture with infested trembling
aspen.
However, a loss of leaves does not mean that the trees are dead.
Trees that have lost their foliage to the caterpillars will
produce a second; less dense set of leaves in five or six weeks.
Although the insect rarely kills healthy trees, it may weaken
them, making them more susceptible to other pests and of course
reducing their annual growth of wood. Damage to the foliage of
sugar maple can reduce the sugar content of sap the following
spring, especially if an infestation persists for several
consecutive years.
CONTROLS
Like most naturally occurring pests, the forest tent caterpillar
has a complete set- of natural control agents which ultimately
bring the infestation to an end. During major outbreaks, an
infestation in any one area tends to collapse in the third or
fourth year. Occasionally, extremely cold weather following an
early hatch of eggs in the spring can reduce caterpillar numbers
or wipe out entire populations. However, the collapse is usually
brought on by overpopulation of the insect. Symptoms of this are
the presence of starved, decaying caterpillars, the total removal
Of foliage from host trees while the larvae are still relatively
young and -the abundance of a parasitic fly. This fly resembles a
e
large hous fly, and is the major parasite of forest tent
caterpillars. The female gives birth to living maggots on the
tent caterpillar cocoon, the maggots crawl through the silk and
subsequently kill the larva or pupa inside.
It is impossible to predict precisely the location and timing of
initial forest tent caterpillar eruptions; the cost of large
scale control operations is high; and this native pest of our
forests rarely. kills trees. For these reasons, it is best to
focus pest management activities.: Such a strategy would centre
on the protection of high-value, high=use. areas until the
outbreak is dampened through the natural causes noted above.
The first step in recognizing a forest tent caterpillar
infestation is the survey for overwintering egg bands. To
determine the number of egg bands on the host trees, examine the
vigorously growing branch tips 'of poplar, maple or oak. Pull
down and examine branch tips until you learn to recognize egg :.
bands If you.-.,fnd them readily you need go no further; you do.
have a :problem;: 'but you may wish to learn about numbers on larger
trees. nnce_:you can recognize egg bands; choose a sunny day and: -
scan branch trigs with binoculars. As 20 egg bands bn' a host tree 8-15 m (.25atoe50 ft) gtalllrepresent a.
heavy infestation. Even fewer egg bands could indicate that you'
have a probiem 'because more susceptible trees ma harbouring
.y be ,-
greater numbers,'-* than the trees you are able to examine carefully
A recognized forest tent caterpillar problem may be dealt with- in
one of three ways: -(a) by removing the egg bands, (b) by
spraying with insecticide, or (c) by planning to avoid activities
in the problem area.`
Removal of egg :bands as a means of control is practical in rather
unusual situations, e.g. , where a property owner has only a few '.
small trees -and can remove all egg bands before egg hatch begins
in early May. Include in your search and removal action both
wild and cultivated fruit trees along with the primary host trees
mentioned earlier, using ladders where required. Throughout
southern Ontario (from Sault Ste. Marie and Sudbury southward)',
egg clusters of the closely related eastern tent caterpillar,
which feeds from a distinct silken tent, may also be found. They
can be distinguished from egg bands of the forest tent
caterpillar by the fact that they are confined to fruit trees and
by their failure to encircle the twig completely. To be certain
of eliminating the forest tent caterpillars remove and destroy
both types.
Insecticides are most effective if applied when caterpillars are
young, i.e. , after the first week of warm spring weather in May.
It is very important to use only registered insecticides and to
FOLLOW ALL LABEL DIRECTIONS. Three insecticides are federally
registered and provincially approved for use against forest tent
caterpillar, and are readily available: (1) a biological
insecticide containing the
referred to as Bt, , (2) a
under the trade 'names Sevin
another contact and stomach
ti
bacteria Bacillus fhuringiensis often*
contact and stomach insecticide
. sold
or Carbaryl, and (3) Methoxychlor,......
insecticide.
Agricultural ground spray equipment may be useful on shade tr ees,
but for forest and- woodlbt protection,-on, best results are obtain '
by using spray-equipped aircraft and experienced operators. ed
Sometimes ear,
1.7 1 4.!.;_1_%jgni Lion, of a Potential fo 7 -
caterpillar -probi4m will rest tent
trouble spots when Pe'r- mit �planning to avoid activities at-
11catdrpillars reach their
likely to be a r Peak. They are not
serious nuisance for more th
Will Coincide ' an'-"a week. This week
with'- the . time they run
host trees and begin Out Of food on the original
n to Migrate en Masse, most likely during the
last week of May or the first three weeks Of June. The first
signs of cocoon Z.�*spinning indicate that wandering will soon cease
since most caterpillars spin their cocoons and disappear at much
the same time. .
Little advice care be,, given, td`,proberty. =owners who, without
warning, -find themselves inundated
Insecticides are-.not %--thousands of caterpillars.
-.not as effective t` ' �1 .
c lve gainst the
caterpillars, and control action a --full-grown
n at this point is difficult it
not futile. The best advice is to gather as many caterpillars as
Possible -where they- are ,concentrated and destroy them
not appeared sudd.enl-* - They have
Y; rather, they may have run Out Of food and
are now dropping.-.or :crawling from the original host trees in
search Of more.
Remember, the forest: tent caterpillar native
only a short time . ive pest, here for
. uMt-il.;` natural con p
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a
back to normal levels' n* ring the Population
b
ACKNOWLEDGEMENTS
Much of the information contained in this publication first
appeared in the Spring 1977 issue of "Your Forests". ( 10,
NO. 1) a former publication of the Private Land Forestry Volume Section,
Forest R-esources. Branc4,- Ontario Mi.nistry Nat
The original al�ticle was written by Dr. Lloof ycf. ural Resources.
Sippell and Mr. Art
Rose, formerly of ,the Forest Insect and Sault Ste. Marie. d Disease Survey Unit in
J. Joseph Churcher -. `
Provincial Forest Entomologist
Pest Control Section
May 18, 1988
lr
Forest Tent Caterpillar, M¢Zacoaoma disatria Hbn.
Forest tent caterpillar infestations
1987, for the third consecutive continued to expand in
moderate-to-severe damage were ma year. All together, 1,649,977 ha ha' in 1986. The bulk of the infestation ise Province of
and Algonquin regions. located in the Northeastern
located aloe g This consists of two large infestations
the Northeastern Region e and in the 'southea8te • one
Y and Temagami districts of
District in the Northern Region, and the other on the eastern shore rn corner of Kirkland Lake
Georgian Bay in Parry Sound and Bracebrid e
Region, with a 8 districts of the Algonquin
Region. small extension intq Huronia District of the Central
$ Numerous smaller pockets of moderate-to-severe dame
from the city of: Sault Ste.
Blind River, Espanola and Sudbur Marie eastward through Sault Ste occurred
District. Sudbury Y districts and the w Marie,
Ba
Sound y, numerous smaller extern North Bay
Bracebridge, . Minden and Bancroft o districts recorded in Parry
Region. Small pockets of the Algonquin
Carleton Place districts of infestation were also ma
Cha lean the Eastern Region,. Peed in La Tweed and
P the of the Northern Region and ' Kirkland Lake and
Northeastern Region. . Further west Wawa District of
defoliation , small patches of moderate-to-severe
occurred in Terrace Bay and Thund
North Central Region and us epockets occurrr Bay istricts of the
ed in
trict of the Northwestern Region. Y Fort Fra
numero
aces Dis-
Egg-band sampling was carried out in
purpose of forecasting forest tent caterpillar n th fall of 1987
for the
hen in mos The x�esullts indicate. Populations in 1988.
"}' t of the areas de �;ribed in the No theaste ions will remain
regions and, indeed, many of the ''smaller rn and Algonquin
fewer but larger blocks .o:f ;moderatex-to-severe
pockets �may co.'aiesce to form
infestations in southeastern defolYation...."
the first areas to sustain defoli tion in In contrast,
Kirkland Lake .District, which, was one
expected to begin declining in 1988 the ...current e
many of the area
988,'-with light .defoliation forecast for
expected e s that were heavily infested in 1987.
northern Huronia District and a levels and Infestations are
similar situation Possibly illxlikely somewhat in
areas infested in Tweed and Carleton Place
probably persist at about the same levels in vesitetrn Wawa Prevail in
in adjacent areas of Populations will
southern Thunder Bay Terrace Bay District strict and
District will western two small pockets in
1988• Infestations in .western Probably' decln_e or
Frances District will probably Atikokari--District and adjacenta Fort
these small Y expands and it is possible
pockets will coalesce to form that many of
year. much larger infestations next
G.M. Howse.
Head, Forest Insect and
Disease Survey Unit
31 December 1987
M.J. Applejohn
Chief of Survey Technicians
ISSN 0832-7173
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