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Plant Health Care Report - The Morton Arboretum · 2017-06-02 · Welcome to the Plant Health Care...
Transcript of Plant Health Care Report - The Morton Arboretum · 2017-06-02 · Welcome to the Plant Health Care...
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June 2, 2017 Issue 2017.5
______________________________________________________________________________ Welcome to the Plant Health Care Report (PHCR). My name is Sharon Yiesla. I am on staff at The Morton Arboretum Plant Clinic, and I am responsible for compiling the newsletter. Comments or concerns regarding PHCR should be sent to [email protected]. To be added to the email list, please contact me at that email address.
Our report includes up-to-date disease and insect pest reports for northeastern Illinois. You'll also find a table of accumulated growing degree days (GDD) throughout Illinois, precipitation, and plant phenology indicators to help predict pest emergence. This newsletter is available online at http://www.mortonarb.org/news-publication/plant-healthcare-report?tid=259
Quick View What indicator plant is in bloom at the Arboretum? Arrowwood viburnum (Viburnum dentatum) is in early flower (Figure 1) Accumulated Growing Degree Days (Base 50): 419.5 (as of June 1) Accumulated Growing Degree Days (Base 30): 2115.5 (as of June 1) Insects/other pests
Rose plume moth
Rose slug sawfly
Four-lined plant bug
Wooly aphids
More sawflies
Carpenter bees Diseases
Apple scab
Sycamore anthracnose
Powdery mildew on ninebark
Brown rot of stone fruit
Black knot
Viruses Weeds
Poison hemlock
Creeping bellflower
Plant Health Care Report Scouting Report of The Morton Arboretum
Figure 1 Arrowwood viburnum (photo: John Hagstrom)
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Degree Days and Weather Information We are once again offering Lisle readings right above the Arboretum readings. The spread between these two sites shows that temperatures can vary over a short distance, which means growing degree days can be quite variable as well.
As of June 1, we are at 419.5 base-50 growing degree days (GDD). The historical average (1937-2016) for this date is 379 GDD50. Since January 1, we have had 20.94 inches of precipitation. Historical average (1937-2016) for precipitation Jan-May is 13.86 inches.
www.gddtracker.net is not working today. GDD numbers are from May 30, 2017, unless noted otherwise.
Location B50 Growing Degree Days
Through May 30 2017
Precipitation (in)
May 26-June 1, 2017
Carbondale, IL* 1056
Champaign, IL* 754
Chicago Botanic Garden** 386.5 (as of 5/31) .41 inches
Chicago O'Hare* 467
Kankakee, IL* 566
Lisle, IL* 490
The Morton Arboretum 419.5 (as of June 1) .59 inches
Northbrook, IL** 367.5 (as of 5/31)
Quincy, IL* 842
Rockford, IL* 409
Springfield, IL* 796
Waukegan, IL* 329
**Thank you to Mike Brouillard, Northbrook Park District and Chris Beiser, Chicago Botanic Garden, for supplying us with this
information.
*We obtain most of our degree day information from the GDD Tracker from Michigan State University web site. For additional locations and daily degree days, go to http://www.gddtracker.net/
How serious is it? This year, articles will continue to be marked to indicate the severity of the problem. Problems that can
definitely compromise the health of the plant will be marked “serious”. Problems that have the
potential to be serious and which may warrant chemical control measures will be marked “potentially
serious”. Problems that are seldom serious enough for pesticide treatment will be marked “minor”.
Articles that discuss a problem that is seen now, but would be treated with a pesticide at a later date,
will be marked “treat later”. Since we will cover weeds from time to time, we’ll make some categories
for them as well. “Aggressive” will be used for weeds that spread quickly and become a problem and
“dangerous” for weeds that might pose a risk to humans.
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Figure 2 Caterpillar of rose plume moth
Figure 3 Rose slug sawfly larvae and damage
Pest Updates: Insects
Rose plume moth caterpillar (minor)
Rose plume moth caterpillars (Cnaemidophorus rhododactyla) are now at work on roses. This
larva is a caterpillar and is approximately ½ inch long. It
is light green with a reddish stripe running from its head
to the middle of its body at one point in its life cycle (fig.
2). The adults are present June through August. New
larvae are produced in fall and overwinter inside the
stems of the rose. They resume feeding in spring (May).
Plume moth larva has been most commonly found near
the tips of rose bushes, damaging the buds and leaves
and sometimes creating some webbing. The caterpillar’s
color blends with the color of new rose growth nearly
perfectly, so they may be difficult to find. A lot of frass (insect feces) is also found in these
areas.
Management: Pruning off infested tips may be the best management advice that can
be offered at this time. Since this is a caterpillar, Bacillus thurengiensis kurstaki (Btk) should be
effective, but is best used when the caterpillars are small.
Rose slug sawfly (minor)
Rose slug sawfly (Endelomyia aethiops) larvae have also been seen on roses. They feed on the
upper layers of the leaf, leaving behind the lower
epidermal layer and creating a "windowpane" effect. The
larvae are greenish yellow with orange heads and are
about ½ inch long when fully grown. They resemble
caterpillars but are not. They are covered in slime that
helps protect them from predators. When larvae mature,
they lose their slimy coverings. Around mid-June, larvae
will drop to the ground to pupate.
Management: Minor infestations of rose slug
sawfly can be controlled by using a forceful jet of water to dislodge the sawfly larvae or by
handpicking. Although this insect looks like a caterpillar, it is not, so Bacillus thuringiensis var.
kurstaki (Btk) will NOT control this pest.
Good website: http://hort.uwex.edu/articles/roseslug-sawfly
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Figure 4 Four-lined plant bug damage
Figure 5 Four-lined plant bug adult
Figure 6 Woolly beech aphid
Four-lined plant bug (minor)
Be looking for the four-lined plant bug (Poecilocapsus lineatus). Our
scouts found a nymph last week. This insect feeds on 250 species,
including many kinds of perennials, vegetables, and shrubs such as
bluebeard, forsythia, and sumac. Feeding injury is frequently
mistaken for leaf spots. Four-lined plant bugs have a piercing,
sucking mouthpart which they use to break plant cells and then flush
the feeding wound with digestive juices. Damage appears as dark leaf
spots which subsequently turn translucent (fig. 4). The damage is
more serious on herbaceous plants than on woody plants.
Sometimes by the time the damage is noticed, the insect isn’t there
anymore. Both nymphs and adults feed on leaves, creating the spots.
Nymphs are red and will develop dark wing pads as they
mature. The adult stage is 1/4” to 1/3” long and has four longitudinal
black lines on its yellow or green back (fig. 5), thus the name. It’s quite a shy insect that scurries
away when you try to find it. The insect overwinters as eggs laid
in slits cut into plant shoots. There is one generation per year.
Management: Some people try to hand-pick these
insects, but their timidity makes them difficult to catch.
Insecticidal soap should take care of larger infestations.
Good websites:
https://www.extension.umn.edu/garden/insects/find/fourlined-
plant-bugs/
Woolly aphids (minor)
The aphids have been showing up on plants, and now
their fuzzy cousins, the woolly aphids are out and about.
We have had reports on wooly beech aphids and woolly
birch aphids. Both these insects look a lot like regular
aphids, except they dress themselves up with a little bit of
white fluff. Like regular aphids, they are sap feeders and
also produce honeydew.
The woolly beech aphid (Phyllaphis fagi) (fig. 6) feeds only
on beech trees (Fagus spp). The woolly birch aphid
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Figure 7 Woolly birch aphids
Figure 8 Spiny oak sawfly
(Hamamelistes spinosus), however, has two hosts, birch (Betula spp.) and witch-hazel
(Hamamelis spp.). The insect overwinters on the bark
of a birch tree. When spring comes, she will give birth
to live young on the undersides of new leaves. The
feeding of the woolly birch aphid causes the leaf to take
on a corrugated look at first (this is the stage we
observed this week). Later, the feeding will lead to
curling of the leaves, with most of the insects tucked
into the lower side of the leaf (fig. 7) and protected by
the curling of the leaf.
In late June, the aphids will go to their other host,
witch-hazel. They will lay eggs on the twigs, and these eggs will overwinter on the witch-hazel.
The eggs will hatch, and the feeding caused by this generation of aphids will lead to the
formation of a spiny gall on the stem. The female produces a number of aphids in the gall, and
then she leaves the gall to fly to the birch.
Management: Both of these woolly aphids are fairly minor pests. They can often be
washed off the plant with a strong stream of water from the garden hose. Insecticides would
not be needed, unless a very high population of insects develops.
Good websites: http://hyg.ipm.illinois.edu/pastpest/200510e.html
http://hyg.ipm.illinois.edu/pastpest/200510f.html
More sawflies (minor to potentially serious) In the May 19 issue, we did a feature article about sawfly larvae. More species of these little
guys have popped up on a variety of plants, some doing a
little damage and some doing a little more. The spiny oak
sawfly larva was found feeding on bur oak (Quercus
macrocarpa). This is an easy one to spot due to the spiny
black hairs on his body (fig. 8). We have also had a report
of a sawfly larvae feeding on the leaves of creeping Jenny
(Lysimachia nummularia). This is most likely Monostegia
abdominalis, which was introduced from Europe. Looks
like it might be a big year for sawflies. Look at the May
19th article for more information on sawflies. Remember
that even though they look like caterpillars, they are not caterpillars. This means that Bacillus
thuringiensis var. kurstaki (Btk) won’t kill them.
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Figure 9 Apple scab
Carpenter bees (minor)
Carpenter bees have been seen in various areas around the Arboretum. Carpenter bees bore
into wood trim, outdoor wooden furniture, porch ceilings, dead tree limbs, and any weathered
wood. They excavate tunnels and can cause damage. They look like bumble bees, but are larger
and have a shiny black abdomen. The males cannot sting. Females will only sting if they are
agitated. They do not nest in living wood. Carpenter bees have strong jaws and chew 1/2 inch
round entrance holes on the underside of wood. They then chew horizontal tunnels up to
seven inches long. The bees are not actually eating the wood. They only create tunnels for
nesting sites. We don’t have any good pictures of this insect, so visit the websites listed below
to see what carpenter bees look like.
Management: Insecticides can be applied to the tunnel entrances on cool evenings
when bees are less active. Do not plug the tunnel entrance. All bees are pollinators, so don’t
kill them unless necessary.
Good web sites: http://www.ces.ncsu.edu/depts/ent/notes/Urban/carpenterbees.htm
http://ento.psu.edu/extension/factsheets/carpenter-bees
Pest Updates: Diseases
Apple scab (potentially serious)
Apple scab is showing up already and is progressing rapidly due to the wet conditions we have
had this spring. We are already seeing
development of the leaf spots. Early lesions
look like velvety, olive-green leaf spots and
will continue to develop into larger, irregular
dark spots Often lesions develop along the
mid-veins of the leaves. Infected leaves
eventually turn yellow (fig. 9) and drop
prematurely on susceptible hosts. This
defoliation can stress and weaken the tree,
especially if it happens year after year. The
fungus which causes scab (Venturia
inaequalis) overwinters on fallen leaves and on lesions on twigs. Sunken spots may appear
later on fruits, and susceptible crabapples can be completely defoliated in severe disease years.
Scab severity is a product of a specific temperature range, duration of moisture on leaves, and
host susceptibility. Scab severity is worse in wet springs, so we can expect to see quite a bit of
this on susceptible cultivars.
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Figure 10 New leaves blighted by sycamore anthracnose
Figure 11 Witches broom
Management: The best way to avoid apple scab is to plant resistant varieties.
“Resistant” just means that, in the typical year, a resistant plant won’t suffer as much from the
disease as a susceptible plant. However, it may exhibit symptoms in “bad” scab years. When
shopping for new crabapples, ask your local nursery which scab-resistant varieties they stock.
Caring for your trees, such as watering during summer droughts, may moderate effects of
defoliation and reduced photosynthesis in affected trees. As the fungus overwinters on fallen
leaves and blighted twigs, collecting and destroying them may help reduce the source of
inoculum next year. Spraying for apple scab needs to begin when leaves begin to emerge and
should continue (at labeled intervals) until two weeks beyond petal fall.
Good websites: http://www.mortonarb.org/trees-plants/tree-and-plant-advice/help-diseases/apple-scab
Sycamore anthracnose (potentially serious)
Earlier we reported on anthracnose on shade trees. We are now seeing anthracnose on
sycamore. The disease may be noticeable now as these large trees leaf out poorly (fig. 10).
Sycamore anthracnose is caused by the fungus
Apiognomonia veneta, and is more serious than the
anthracnose we see on other shade trees. Sycamore
anthracnose is common when we have cool, wet weather
during leaf development. Considerable defoliation may
occur in late spring, but trees normally bounce back and
produce a second set of leaves in early July that remain
disease-free. Leaves that are infected in early spring
often turn brown and shrivel while still small and may be mistaken for frost damage. Leaves
that are infected in late spring may show brown foliar lesions that extend along the veins, often
in V-shaped patterns. The leaves turn brown and may drop prematurely.
There are two other stages of this anthracnose: shoot and
leaf blight and canker formation. Shoot and leaf blight
results when the pathogen enters succulent shoots. It
causes the rapid death of expanding shoots and leaves. The
pathogen overwinters in twigs and is active whenever
temperatures are high enough in the fall, winter, and
spring. During winter, cankers form on infected shoots and
kill the buds. Repeated infection results in deformed shoots
and witches brooms (dense clusters of twigs). Although this
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Figure 12 Powdery mildew on ninebark
disease can weaken trees and increase their susceptibility to attack by other pathogens and
pests, it is not lethal.
Management: Dead twigs should be pruned as they develop throughout the growing
season. Rake and discard fallen leaves to reduce the source of inoculum. It is impractical to
spray fungicides on large trees, but for smaller, specimen trees, the disease can be controlled
with fungicides applied as leaves are opening. Systemic fungicide injections can also be used. If
you want to plant a Platanus species and don’t want to worry about sycamore anthracnose, you
can plant a hybrid planetree, that is resistant to the disease. Two common cultivars can be
seen on the Chicagoland Grows website (http://www.chicagolandgrows.org/index.php)
Good website: http://www.mortonarb.org/trees-plants/tree-and-plant-advice/help-
diseases/anthracnose-shade-trees
Powdery mildew on ninebark (minor to potentially serious)
We have not seen a lot of powdery mildew yet this season, but it is showing up on the leaves of
ninebark (Physocarpus opulifolius). The straight species of ninebark is relatively resistant to
powdery mildew, but some of the cultivars can be very susceptible and can sustain quite a bit
of damage. University of Connecticut has done some research on this. Go to
http://www.academia.edu/14492054/Susceptibility_of_eastern_ninebark_Physocarpus_opulif
olius_L._Maxim._cultivars_to_powdery_mildew to see their findings. Hundreds of plant
species are susceptible to powdery mildew, but the disease is caused by many different species
of fungi which are host specific. This means that the powdery mildew on coralberry will not
infect lilacs and so forth.
Powdery mildew appears as a superficial white to
gray coating over leaf surfaces, stems, flowers, or
fruits of affected plants. Initially, circular powdery
white spots appear. These spots coalesce producing a
continuous patch of “mildew.” On ninebark, the tips
of branches often develop a thick coating of white
powder (fig. 12), while other parts of the same plant
may show very few symptoms. Later in the season,
fungal fruiting bodies that look like black pepper
under a hand lens will appear. Warm days and cool
nights favor this fungal disease, and we have been
seeing this type of weather this year. The fungi that
cause powdery mildew are deterred by water since spores will not germinate in on leaves.
However, the fungus still needs high humidity to infect the plant. Leaf curling and twisting
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Figure 13 Leaf blight caused by brown rot
result, and in severe infestations you may see premature defoliation and deformed flower
buds. Although unsightly, powdery mildew is usually not fatal in the landscape.
Management: Infected plant parts should be removed as soon as symptoms appear.
Dispose of fallen leaves and do not handle plants when foliage is wet. Water plants during
periods of drought to keep them healthy. High humidity can increase disease severity so avoid
overhead watering in late afternoon or evening. Put plants in locations where there is good soil
drainage and sufficient sunlight. Provide proper plant spacing for good air circulation. Powdery
mildew on some plants can result in significant damage, and fungicides may be needed. To
obtain optimum results, spray programs should begin as soon as mildew is detected. In the
future, plant mildew-resistant cultivars and species.
Good website:
http://www.mortonarb.org/trees-plants/tree-and-plant-advice/help-diseases/powdery-
mildews
Brown rot of stone fruit (serious)
The Plant Clinic at The Morton Arboretum has received a couple reports of brown rot on
cherries. Brown rot is caused by the fungus Monilinia
fructicola which can infect peaches, plums, cherries,
apricots, and other Prunus species. The disease is
sometimes seen as blossom blight – the browning and
sudden collapse of blossoms. The infection can spread
into shoots and twigs during the next several weeks
resulting in shoot and twig blight (fig. 13). This is the
stage we observed. Cankers, which may be
accompanied by a gummy ooze at their margins, form
on twigs often causing twig dieback. Infections of fruit
start as brown spots that rapidly infect the entire fruit, completely covering it with spores and
giving it a fuzzy look. Infected fruits decay and shrivel; some will stay attached to the tree
throughout winter while others will fall to the ground. These ‘mummies’ provide inoculum for
the following spring.
Management: Sanitation is crucial to control of brown rot. Prune out active infections
immediately during dry weather. Don't forget to disinfect pruning tools. Rake and clean up
debris under the tree during the summer to remove fallen leaves and fruit. Prune to promote
good air circulation through the tree canopy. Wild or neglected stone fruit trees (e.g., wild plum
and cherry) in the area are likely to have the disease and be sources of inoculum that should be
removed. Later in the year remove rotted fruit ‘mummies’ that are persistent, and prune out
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Figure 14 Old black knot (left) and newer infection (right)
cankers and infected twigs. If damage is severe, fungicides need to be applied when blossoms
first open in early spring.
Good websites: http://ohioline.osu.edu/hyg-fact/3000/pdf/HYG_3009_08.pdf
http://www.ag.uiuc.edu/~vista/abstracts/a804.html
Black knot (potentially serious)
Black knot (Dibotryon morbosum) is a serious and widespread problem of trees in the genus
Prunus, especially plum and cherry trees. The
Plant Clinic at The Morton Arboretum receives
questions on this problem year round since it is so
prevalent and so easy to spot. Now is the time to
look for new abnormal swellings on branches of
cherry, peach, plum and related trees. The fungus
overwinters in the hard, brittle, rough, black
“knots” on twigs and branches of infected trees
such as wild black cherries in the woods (fig. 14).
These knots may be small or may be several inches long and wrap around the branch. In some
instances the main trunk of the tree can become infected.
In the spring, the fungus produces spores within tiny fruiting bodies on the surface of these
knots. The spores are ejected into the air after rainy periods and infect succulent green twigs of
the current season’s growth. The newly infected twigs and branches swell. The extensive
overgrowth of bark and wood is a response to hormones and produces the smaller swellings
that we are now seeing. Frequently these swelling are not noticed the first year. The swellings
become dormant in winter. But the following spring, velvety, green fungal growth will appear
on the swelling. The swellings darken and elongate during summer and, by fall, turn hard,
brittle, rough and black. The black knots enlarge and can girdle the twig or branch, eventually
killing it.
Management: This is a difficult disease to manage. Prune and discard all infected
wood during late winter or early spring before growth starts and when new swellings appear.
Pruning cuts should be made at least six inches below any swellings or knots. In advanced cases
with many knots, pruning out branches may not be feasible as it may destroy the shape of the
tree.
Good web site: http://www.mortonarb.org/trees-plants/plant-clinic/help-diseases/black-knot-ornamental-cherry-and-plum
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Figure 15 Tobacco rattle virus on epimedium
Figure 16 Poison hemlock has a spotted stem
Viruses (some minor, some potentially serious)
We are starting to see some plants exhibiting viral symptoms already this year. We have seen a
virus on geranium and tobacco rattle virus on
barrenwort (Epimedium spp.) (fig. 15). We have
also received a report of mosaic virus on Katsura
tree (Cercidiphyllum japonicum). Viruses seldom kill
their hosts, but the plant will always be infected and
many viruses can be spread by insects that feed on a
diseased plant and then move to a healthy plant to
feed. Virus symptoms can vary by plant and by virus.
Common symptoms include mottling, mosaic
patterns and excessive growth of plant parts.
Management: There is no chemical
management of viruses. Once the plant is infected, it cannot be ‘cured’. There are two options
for dealing with viruses. First, you can keep the plant and live with the fact that it has the virus.
For some plants this is an acceptable option, especially if it does no serious damage to the plant
or there are no other plants of the same species nearby to become infected. The second option
is to destroy the plant. This is a good idea with small plants like roses, hostas or raspberries
where there are other plants of the same species nearby that might become infected.
Weeds Poison hemlock (dangerous)
The Plant Clinic has been receiving reports of poison hemlock (Conium maculatum) popping up
in home gardens. This weed has been fairly prominent for
the last few years, not only in home gardens, but popping up
along the side of the road in many areas. Poison hemlock is a
member of the carrot family (which contains both edible and
toxic plants, so beware!!). Most members of this family have
the same type of umbrella-shaped flower cluster know as an
umbel. Because the flower cluster of Queen Anne's lace and
the flower cluster of poison hemlock look similar, plants may
be incorrectly identified. This can lead to contact with a
dangerous plant.
Poison hemlock is a large, non-native plant (often 6 feet or
more). The smooth stem is stout, has a ridged appearance
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Figure 17 The ferny leaves of poison hemlock
Figure 18 Creeping bellflower
and is marked with purple spots (fig. 16). The stem is
hollow. Leaves are large and very ferny in appearance
(fig. 17). Poison hemlock is a biennial plant, which means
it will form foliage in the first year and flower and set
seed in the second year. Plants in their second year are
starting to flower and have the typical white flower
cluster (umbel) of the carrot family. Queen Anne's lace
has one red floret in the center of its flower cluster,
poison hemlock does not.
All parts of the plant are toxic and may lead to death if
ingested. The plant's oil may be absorbed through the skin, so long sleeves and gloves will be
needed when handling the plant.
Management: Plants can be cut down or dug out. This should be done before the plants
go to seed and is most easily done when plants are small. Cover your skin during this process.
Do NOT burn the plants. In spring, small, actively growing plants may be treated with an
herbicide containing glyphosate.
Good websites: http://hyg.ipm.illinois.edu/article.php?id=380
http://www.btny.purdue.edu/weedscience/2003/articles/PHemlock03.pdf
Creeping bellflower (aggressive)
For the last few years, we have been receiving reports of an annoying weed making itself
known in flower gardens and lawns. There are actually
two plants that are nearly identical, ladybells
(Adenophora spp.) and creeping bellflower
(Campunula rapunculoides). The two plants differ only
by a small structure within the flower. Ladybells and
creeping bellflower are closely related, but on doing a
little research, it seems that the creeping bellflower
may be the ‘bad seed’ of this family. It is the one that
seems to be overly aggressive. Unfortunately, because
the plants are so identical, if a friend shared some
ladybells with you from her garden, you may actually
have creeping bellflower.
Young plants have leaves that are heart-shaped to lance-shaped (fig. 18). This innocent looking
plant has fleshy roots growing horizontally under the soil. These fleshy roots help to spread the
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Figure 19 Patch of creeping bellflower
plant and before you know it you have a healthy patch of them in your flower bed (fig. 19). If
the plants are not removed, a flowering stalk with
purple, nodding, bell shaped flowers will form.
Management: Plants can be removed
manually through digging, but any roots left will
continue to produce new plants. As new plants
develop and are actively growing, spray them with a
weed killer containing glyphosate. Glyphosate will be
absorbed by the leaves and taken down to kill out the
roots. Do not get the glyphosate on desirable plants
as it will kill them as well.
Bartlett Tree Experts, Presenting Sponsor of the Plant Clinic.
The Plant Health Care Report is prepared by Sharon Yiesla, M.S., Plant Knowledge Specialist and edited
by Fredric Miller, Ph.D., Research Entomologist at The Morton Arboretum and Professor at Joliet Junior
College; Doris Taylor, Plant Clinic Manager, and Carol Belshaw, Arboretum Volunteer. Frank Balestri
M.S., Plant Health Care Technician/Research Assistant is responsible for coordinating the scouts. The
information presented is believed to be accurate, but the authors provide no guarantee and will not be
held liable for consequences of actions taken based on the information.
Thank you...I would like to thank the volunteers who will be scouting for us this season. They find most
of the insects and diseases reported here. The Scouting Volunteers include: Maggie Burnitz, LeeAnn
Cosper, Ingrid Giles, Emily Hansen, Ann Klingele, Pat Miller, Loraine Miranda, Julie Moore, Mary Noe and
Wendy Vichick . Your hard work is appreciated. Thanks also to Donna Danielson who shares her
scouting findings.
Literature/website recommendations:
Indicator plants are chosen because of work done by Donald A. Orton, which is published in the book
Coincide, The Orton System of Pest and Disease Management. This book may be purchased through the
publisher at: http://www.laborofloveconservatory.com/
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Additional information on growing degree days can be found at:
http://www.ipm.msu.edu/agriculture/christmas_trees/gdd_of_landscape_insects
http://extension.unh.edu/resources/files/Resource000986_Rep2328.pdf
The Commercial Landscape & Turfgrass Pest Management Handbook (CPM), for commercial applicators,
and Pest Management for the Home Landscape (HYG) for homeowners from the University of Illinois,
are available by calling (800-345-6087).
This report is available as a PDF at The Morton Arboretum website at
http://www.mortonarb.org/visit-explore/news-events/arboretum-news?tid=259
For pest and disease questions, please contact the Plant Clinic at (630) 719-2424 between 10:00 and
4:00 Mondays through Saturdays or email [email protected] . Inquiries or comments about the
PHCR should be directed to Sharon Yiesla at [email protected] .
Copyright © 2017 The Morton Arboretum
Not printed on recycled paper, or any paper for that matter.