General Information
April 22, 2017
My Mayhaw (Riverflat Hawthorn, Crataegus) crop was a 100% failure last year due to
cedar gall rust. I have removed all nearby cedar trees possible. What else can I do?.
Cedar rust is the disease which has two hosts to complete its life cycle—members of the eastern red cedar (juniper) family and the apple, quince or hawthorn family. These rusts can infect most varieties of eastern red cedar (Juniperus virginiana) as well as many other junipers and an alternate host. Of these alternate hosts, cedar-apple rust is primarily a disease of apples and crabapples but it sometimes infects pears, quince, and serviceberry but in some years it can infect other plants in the rose family. Removing cedar trees in your yard usually won’t be enough, since the disease can cover a large radius. If we have a wet, rainy early spring the disease tends to worse and heavy rains within the first two weeks of bud break and leaf growth can cause the disease to be more severe. The only foolproof method to protect your plants is applying a fungicide as your plants begin to leaf out in the spring as a preventative application when the spores are on the junipers.
(September 2015)
I have some Gerber daisies in clay pots on my back porch, they have been beautiful and bloomed often. Just last week the leaves on the plant have all developed what looks like a fungus on the leaves. I have sprayed Bayer Advance with no improvement. Could you tell me what causes this condition and what to do about it? I have enjoyed the plants for two years. They were in the garage during the winter and even bloomed there.
Don’t expect immediate results from fungicide sprays. Diseases don’t happen overnight, and control won’t either. Spots won’t disappear with spraying, but new growth should come out that is healthy. You don’t mention exactly what is happening, but if you have powdery mildew –a white growth on the foliage, that can occur with periods of high humidity. If it is leaf spots, plants that get stressed can have some this late in the season. Gerber daisies are considered relatively short-lived perennials if left outdoors year-round. If only a few leaves are affected, remove them. Lightly fertilize, since the plants have a good couple of months of growth left before you move them back into the garage. Let them dry out a bit in between watering
(December 2012)
I have a question about some trees in my yard. I have a number of post oaks in my
yard, and I am finding a growth of some sort on the underside of many of the leaves.
I have attached a photo. Can you tell me what this is and whether it is a problem
that needs to be treated? There are many of them, and I don’t find them often on
oak leaves from other yards. I live in Fayetteville.
You have a gall on the leaves. Galls can look frightening, but cause little damage,
when on leaves. They can be hard shelled or fuzzy, and some even come with polka dots!
Galls can be caused by insects or a fungus, but in this case it is caused by a small
mite. They are nothing to be concerned about. Occasionally different species of galls
form on small branches or twigs, and these can do harm, but yours is common on trees
everywhere.
(July 2012)
I have tomatoes in size ranging from dime size to silver dollar size. A large number
of these tomatoes have dark brown and/or black areas at the bottom of the tomato.
What is causing this and what can I do?
Blossom end rot has started in our gardens. Although it looks like a disease, it
is actually a calcium deficiency which affects some varieties more than others. It
often hits our gardens when it has been really dry and we get a downpour of rain.
Fluctuating water levels make it much worse. Try to mulch your garden and keep it
as evenly moist as possible in these dry days. There are some calcium sprays like
Stop Rot or calcium chloride which can help, but even watering and mulch should also
do the trick. It won’t correct the tomatoes that have the problem, but should prevent
more from succumbing.
My oak tree has some round ball things attached to the underside of some leaves.
Do you have any idea of what this is and how I should control it? Will it kill the
tree?
The problem is a gall. Galls can be caused by insects or diseases, but more commonly
on oaks they are insects. They can be very showy—some even have red polka dots. They
come in all colors and sizes and if only on the leaves I would not worry about them.
There is an oak gall that can attack some trees that can cause damage, but it gets
on small stems and twigs, not on the leaves.
(June 2012)
I had a beautiful Lilac Bush that was just gorgeous Easter day. It had more blooms
than it ever has. We planted it 6 years ago. It came through the summer heat last
year just fine, and then within two weeks after Easter, the bush was dead. The leaves
were all dried up and curled. No sign, that I could see of bugs. Could you tell me
what could cause this? I have another lilac bush 30 feet away, and it is fine so far.
The fact that it died so quickly indicates something has either killed the roots or
girdled it at the soil line. It could be either a root rot or borers. Check the plant
at the soil line for signs of borers, holes in the stem. If you have a heavy soil
and it got overwatered it could be a root rot. When you remove the plant, check the
root system. Is it full and white, or black and slimy? Is there any odor? These
are all indications of root rot. If you still can’t determine any cause, take it
to your local county extension office to send to our disease diagnostic lab.
(April 2012)
Our family moved into a new house in January. We have a tree in our landscaping near
the house, and I'm not sure what it is. The parts that are blooming and leafed out
look healthy and pretty. However, there are several branches with nothing on them.
I'm not sure if I should go ahead and cut those branches out now, or if I should wait
until after it's done blooming. If I cut them all out, there may not be much left.
Also, do you know what could have caused this? There doesn't seem to be any fungus
or pest on it anywhere that I can see.
The tree in question is a flowering cherry. They are one of the most beautiful spring
flowering trees, but not the longest lived in our area. The trees are susceptible
to a host of insects and diseases, with borers being quite common. The fact that
your house was for sale probably during last summer, could also have played a factor.
If it wasn’t watered as well as it could have been, that would have stressed it even
more. I would go ahead and cut out all the dead wood, enjoy what few blooms it has
and then shape those branches to see if you can restructure the tree. Once it is
bad as yours is, probably an easier alternative would be to plant another tree nearby
and remove this one eventually.
(Feb. 2012)
I know it's hard to tell from a photo but my magnolia is sick. The leaves are falling
off and the remaining leaves are turning yellow and limbs with no leaves. There appears
to be a scaly grayish fungus growing on most limbs. Is there a treatment for his condition?
I can tell by the photo that your tree is sick. The foliage is yellow and there isn't
near enough of it. Did you water this past summer? You may have scale insects, but
to determine what you have, take a branch in to your local county extension office.
As old as your plant is, and as scrawny as it has become, I don't know what kind of
turn-around you are going to have, but let’s get it diagnosed and if it is insects,
we can handle that, start fertilizing this spring, water and see what happens.
(November 2011)
I have a mysterious fungus on my bush known as the burning bush. It had little apples
on it first, when they fell off the fungus appeared. Do you know what could have
caused the fungus to grow?
It is not a fungus but an insect called wax scale. The wax scales are one of the
larger scale insects with a white waxy coating which protects the insect. Prune out
any branches that are covered in them, and then spray with a dormant oil after all
the leaves have fallen off. Dormant oil works by smothering out the insects, so thorough
application is necessary. Dormant oil is a good approach on deciduous plants because
you can get good coverage. With evergreen plants it is difficult because the leaves
are dense which makes coverage more difficult. You can also use a systemic insecticide
containing Imadicloprid in late winter. Be aware that once dead, the scale will not
fall off the plants, but the large white ones will turn a dull gray color.
I have a twelve year old Henryi clematis that was diagnosed this past summer with
Clematis Wilt. They recommended that I cut it all the way back to the ground and
said that it would possibly come back in the fall. It did and looked healthy for
about a month and even sent out one new blossom. However, now the leaves are starting
to brown on the edges just like it did during the summer. I suspect that the browning
is the "wilt". Your thoughts would be appreciated.
I would be very surprised if clematis wilt were showing itself again this late in
the season. I would suspect it is natural leaf drop for the winter. Clematis wilt
is tricky. It tends to be worse on large flowered forms and in heavier soils. Sometimes
transplanting it to a new location and planting it high can help. In some varieties,
this disease occurs annually killing it to the soil line for several years, and then
the plant seems to outgrow it and you never get it again. I am surprised it just
hit yours since it is 12 years old and I am assuming in the same location. Good luck.
I have several 'Otto Luyken’ laurels in my front yard that look like they have taken
a beating. They face east and get early morning sun, which was pretty brutal this
year, although I watered pretty regularly. It also looks like some kind of insect
has been eating them. One of the bushes has dead branches on one side, so I've been
trimming that one. I guess my question is, are they goners, or will they perk up in
the spring? They are a significant part of my front landscaping, so I sure would hate
to lose them.
A lot of plants took a beating this summer, but for now, leave them be and see what
happens next spring. As they begin to grow in the spring, assess how much damage
was done, and if they are greening up, consider corrective pruning then. There is
a disease known as shot hole fungus that causes tissue to fall out and leaves perfect
holes in the leaves. Don’t spray now, let’s just see what happens in the spring.
(December 2011)
My azaleas are turning yellow. Is this a disease or deficiency of some kind? I have
several varieties and all are turning yellow.
Look around at other yards and you will see you aren’t alone. This is a common problem
every year. Even though the azaleas are evergreen, they shed old leaves annually.
Light pink and white azaleas turn yellow before their leaf shed, while darker flowering
forms usually turn reddish shades. It looks alarming since it is so all encompassing,
but if you look closely, the leaves closest to the tips of the branches and the flower
buds are still intact.
(November 2010)
When I plant my tomatoes in the ground they start out pretty good for the first two
weeks. Then when they start coming up, during the next two weeks they just start drying
out. After blooming and producing the tomato the same problem is occurring. As the
blooms come out they will dry and fall off. Needless to say the tomatoes plants have
a short life span. They will totally stop producing around the middle of the summer.
I was told by the agriculture dept. that I was probably splashing water up on the
plants too much when watering. This last year I only had a soaker hose on them. The
agent said to put straw down around the bottom of the plants, but to no avail. Maybe
there is a better method that you can help me with. Are there other solutions that
you might know?
First, get your soil tested. Take a pint of soil to your local county extension office
and see what the pH is and the levels of N, P and K. I always want to start with
the foundation of the plants, which is the soil. If your soil is pitiful and rocky,
you can enrich it with compost. How is the drainage? If they are sitting in waterlogged
soil, they will die quickly. We recommend that you rotate where you plant your tomatoes
every year because many tomato diseases are soil borne, and attack the plants earlier
each season, but problems beginning within two weeks of planting is pretty amazing.
I think we might have something else going on. Mulching the plants to keep soil from
splashing on the stems can slow down the disease spread, but again, it doesn't usually
occur within two weeks of planting, nor does it cause the flowers to dry. Most tomato
diseases either start with the leaves dying from the bottom and it progresses up the
stem, or we have a dramatic wilting and dying from one of the vascular wilts. It
sounds like your problem is more about fruit set than plants dying. How much sunlight
do the plants get? They need at least 6 hours a day. Some varieties quit setting
fruit when the temperatures get above 90 degrees during the day or stay above 75 degrees
at night, but if the plants look good, they can kick back in and produce well into
fall. I think we need to investigate further.
(October 2010)
I have taken up some aucuba that I had growing on the north side of my house after
they wilted and turned black. I also have some oakleaf hydrangeas that developed
reddish brown spots on them in the same area. We cut them back a couple of years
ago, raked up the old leaves and mulch, and they came back ok. We didn't have any
flowers last year, but this year we sprayed with a fungicide and we had lots of flowers.
Now late in the season, but later on the red spots are back. What do we do to get
rid of whatever it is that is causing our problem? Our tomatoes and peppers in small
bed on the east side of the house are also affected. Would you advise replacing the
aucuba with healthy plants or going to a more disease resistant plant?
How much sunlight were the aucuba getting--also the oakleaf hydrangeas? We have had
several situations where trees were removed or damaged and the plants were simply
getting too much sun. Aucuba turn black in direct sun. This year, many oakleaf and
regular hydrangeas have leaf spots. It isn't all that rare late in the season, nor
would I recommend starting a spray program this late. If the problem starts early
in the year then a fungicide might we warranted. Water is still the most vital factor
for success in a garden, and this year that was a challenge. Lack of fertilization,
heat and drought stress are probably your biggest problems with the vegetables. I
do not think the same thing is plaguing all your plants, but it has been a tough gardening
season.
(August 2010)
Behind my house is a white oak tree. It is approximately 40 to 50 years old, stands
well above our wood deck. It shades our deck and the pool below. Overall it appears
very healthy. Every year, however, it starts losing leaves about July 1st. I have
a major cleanup of fallen leaves almost daily. There is an almost identical oak,
same age and variety about ten feet away with similar surroundings that loses no leaves
at all until fall. I feel the tree is infested with something. At any rate, what
can be done about the problem?
If the tree does this every year, obviously it is not causing any major damage, since
the tree looks healthy and fully leafs out each spring. This year, there are numerous
trees which are shedding large quantities of leaves due to lack of water. You can
really tell which trees are getting supplemental water and which aren't. I would
have had a hard sell with this theory last year because of all the rain. Are there
any symptoms of disease or insect attack on the leaves that are falling? Keep in
mind that trees have extensive root systems. It is possible that this tree has limited
roots due to the pool, house, etc. You can take a sample of the leaves into your
county extension office. Examine the trunk, make sure there are no wounds or growths
there, but if it is full and healthy every spring, I am not too concerned.
(July 2010)
HELP, my azaleas are dying! We have well established azaleas, planted in 1995 and
now they are dying. It started last year with one or two and now several are going.
We live in mid-town, Little Rock, and have a sprinkler system. Our house faces South
and the azaleas are across the front and back. The ones in the front started first
and now the ones in the back are affected. We trimmed them back this year and fertilized,
however we have not removed old mulch. The leaves turn yellow and sections of the
plant dies first, then the whole plant. I have not seen any sign of insects. The watering
system is set for 3 times a week at 10 minutes each time. Am I watering too much?
Could there be disease from the old mulch?
To properly identify what is going on, take one of the dying plants or at least a
portion of the stems plus roots to your local county extension office so they can
send it into our disease diagnostic lab. There are several diseases it could be but
we need to know for sure what is causing the problem before you start trying to control
it. I think watering for only 10 minutes three times a week is wetting the soil surface
more than deeply wetting the soil. The goal in watering is to water deeply and infrequently.
Soil type, amount of sunlight, and what you are growing are all factors in frequency
and duration of watering
(April 2010)
I am having difficulty with my fruit trees. Last year my peach tree produced lots
of peaches, but they all dried up around the seed before they ripened. I also noticed
that quite a few of the leaves and small branches dried up and died. My apple tree
made really good apples but the leaves dried up and died and I noticed yellow spots
on the leaves that had several round dots in them. I assumed these to be some kind
of insect eggs. The apples also had dark spots on them. I have already cut them back
and am hoping that you can suggest some kind of spray, preferably something natural
that I can use to solve these problems
Fruit trees can be challenging for the home gardener, especially peaches which have
numerous insect and disease issues. Brown rot is the most destructive and can wipe
out a crop seemingly overnight, especially when we have periods of rain, which were
almost constant last year. Pruning is something you will need to do annually, but
a spray schedule is also necessary to produce quality fruit. Purchase a home fruit
spray which has both an insecticide and a fungicide mixed together. There are organic
products as well as non-organic. Start spraying when two thirds of the flower petals
have fallen and then continue throughout the growing season, about every 10 days to
three weeks depending on the weather. Your apple tree sounds like it was infested
with cedar apple rust. This disease has two hosts--Eastern red cedars and apple trees.
By the time you see yellow spots rimmed in orange it is too late to spray to control
it. The key is to do preventative sprays the first few weeks following bloom. Orange
gelatinous masses form on cedar trees releasing spores which then infest the apples.
Typically apple diseases are a bit easier to deal with since you can usually peel
off the damage and still eat the fruit. Spray schedules, cultural information and
pruning guides are available on our Extension website at: http://www.arhomeandgarden.org/
(June 2010)
Is there any way to treat soil that would help fight tomato wilt? The only information
I can find in garden books is to "buy disease resistant plants" and throw away the
ones affected. I bought disease resistant plants and for the second year in a row,
my tomato plants are healthy and have tomatoes on them one day and are wilted and
dead the next. It is very discouraging. Can I plant anything in the fall (like clover)
that might aid in cleansing the soil?
Many tomato diseases are soil-borne. That means they persist in the soil for years
and can attack your tomatoes quicker each season. Planting disease resistant varieties
helps, but only to a point. For one thing, disease resistance doesn’t cover every
disease out there. Secondly, a new strain of the disease can build up especially
if you plant over and over again in the same area. Rotating tomatoes in the garden
is ideal, but again, that alone may not do the trick. The best idea is to sterilize
your soil using soil solarization. Till the soil as deep as you can, then saturate
the soil, getting it really wet. Once you have wet the soil, cover it with clear
plastic, making firm contact between soil and plastic. Leave it covered for six to
eight weeks between July and September and you should start off with clean soil next
year. Cover crops such as clover and vetch can help to build up your soil, but do
little to control diseases. You can also take a plant sample in to your local extension
agent when you have the disease, they can pinpoint exactly which disease issue you
have.
(July 2005)
My tomatoes have died because of what I think is a blight. If this is in the soil
of my garden, is there any way I could sterilize the soil so I could plant some late
tomatoes and have some this fall? Is there some fungicide I could use that would
prevent it?
There are numerous diseases that plague tomatoes. Early blight, septoria leaf spot
and late blight cause the “firing” up of the lower leaves. It usually takes the plant
by the end of the season, but you usually have had a good harvest by then. Sprays
weekly of a fungicide such as Maneb or Bravo can help to prevent it. If your plants
out and out died already, you may have one of the more serious vascular wilts. These
soil borne diseases can kill a plant within a few days time once they hit. Soil sterilization
can be done via the sun—called soil solarization. Chemical products are no longer
available to the home gardener. To solarize your soil, till it thoroughly, wet it
completely, then cover it with clear plastic, making firm contact between soil and
plastic. Leave it covered for six weeks. Then you can replant. You could have a
good crop of fall tomatoes. You could also get them growing in large containers.
Tomatoes can be container grown all season, just keep up with the watering.
(April 2010)
I have a Leyland Cypress that died last year, turning brown from the bottom up.
Now I notice two branches on a nearby Leyland that is beginning to turn brown. Do
I have bugs, fungi, parasites or chemical poisoning? Or is the Leyland going the
way of the red-tipped photenias? Help.
I think the Leyland is going the way of the red tip photenias, but be aware that some
red tips have not been affected by disease and some Leyland’s haven’t either, but
disease is spreading on both plants. There is a canker disease that affects Leyland
cypress and there isn't much you can do once it hits. It is typically associated with
some type of environmental stress. All of our rains last season did not bode well
for many of the needle type evergreens. Here is a link to our fact sheet about the
disease: http://www.uaex.uada.edu/publications/PDF/FSA-7536.pdf If you are replacing
the plants, I would consider other options--Emerald or Green giant arborvitae; cryptomeria,
or one of the hollies.
Have you had any other comments about the clematis vines just drooping over night
and looking wilted? One day they were beautiful, then the next they were looking
sad and wilted. They eventually began to grow back at the base, but I did not get
any flowers after that.
It sounds like your clematis is suffering from a disease called clematis wilt. This
disease tends to be an issue on large flowering early blooming varieties. It is often
worse in heavier soils or soils that do not drain well. Unfortunately, the disease
often attacks the plant right as it is about to start blooming. The disease enters
the stem and clogs the vascular system, cutting off the supply of food and water to
the top of the plant, causing it to wilt and die, seemingly overnight. It only affects
the plant at the soil line, leaving the crown and root system unaffected. The plant
eventually grows back from the roots, but if yours is a spring only bloomer, you have
lost the flowers for that season. All season bloomers, can rebound and still bloom.
Some gardeners are plagued with this disease annually until they raise the level of
planting or move it to a new location. Others find that as the plant matures it seems
to outgrow the problem.
(May 2010)
I live in northwest Arkansas and we have some small cedar trees at the edge of our
lawn that has some orange (fungus?) looking things growing out of grey nuts? They
look like a bunch of tentacles and are mushy. Are these harmful to the cedars?
What you are seeing with the bright orange tentacles is the fruiting body of cedar/apple
rust on your cedar tree. This disease has two hosts--Eastern Red Cedar and apples/crabapples.
The disease first starts on the cedar. During periods of rain in the spring the galls
quickly grow orange, gelatinous tentacles that produce spores which then blow to
the developing fruit and leaves on nearby apple and crabapples trees. Symptoms will
appear on apple foliage as small round orange spots which then yellow. Heavy infestations
can cause the apple trees to shed foliage and deform the fruit lightly, but the disease
is not deadly to either plant. If you desire clean fruit, fruit sprays are needed
in early spring. They are only effective during the time the spores are active in
early spring, and once you see symptoms, sprays are no longer effective. If you don’t
grow apple trees, you can ignore them or simply enjoy their odd appearance. Here
is a link to a fact sheet for more information: http://www.uaex.uada.edu/publications/PDF/FSA-7538.pdf
(October 2007)
My rose bush has black spots on the leaves and they turn yellow and fall off. I have
sprayed it with disease spray from the gardening center but it hasn’t helped. Now
it has almost no leaves and looks like it could die. It usually blooms a lot in the
spring and summer, but this year it only bloomed in the spring and has been pitiful
ever since. I have had it for about 10 years and don’t want to lose it. What can
I do? Also there was an ant bed underneath it (small black ants and we sprayed them,
could they have damaged the plant?
Your rose bush has the classic rose fungus disease called black spot. This was a
great season for diseases of all types, but if you have a susceptible variety, you
typically have the disease every year in Arkansas. Spraying after you see the disease
is usually a futile attempt at control. The key is to start your spray schedule in
advance of the disease—soon after the plant kicks into growth in the spring. Sprays
every week to three weeks—depending on what product you use, will be necessary throughout
the season. Black spot can weaken a rose bush, and if it occurs year after year, it
can weaken it enough for it to die, but it should come back strong next spring with
proper pruning, spraying and fertilization. I don’t think the ant spray had any effect.
(June 2008)
I have planted some tomatoes in pots and all seem to be okay except one which the
leaves are curling on and it does not seem to have as deep green color to the leaves.
What could be the problem? Also what causes the blossom end to rot and what can be
done for that?
Leaf roll (curling of the leaflets) is a physiological condition that occurs most
commonly when plants are trained and pruned. Any type of stress can cause leaf roll.
It usually does not affect fruiting or quality, and it is not a disease. Leaf roll
is a common genetic trait in some varieties but it is typically not associated with
a difference in leaf color. Monitor these plants, make sure you are watering enough,
but don’t drown them either. Use a water soluble fertilizer and see if that helps
with the color. Blossom end rot is a calcium deficiency that is usually brought about
with huge fluctuations in moisture levels—we often see if when we go through a dry
spell and then have a downpour of rain. Even though your plants are in containers,
mulch the soil to aid in keeping the moisture levels more constant.
(June 2009)
My tomatoes have developed on the bottom leaves a blight which is yellow. The leaf
slowly dies completely. The disease works to the top of the plant and finally kills
the plant. I have had the same problem for the last couple of years. This year I
am using Ortho's Garden Disease Control, spraying twice a week. I wonder if I am using
the right fungicide or I use something else? I am also wondering if the blight is
in the soil.
Tomato plants suffer from a variety of soil borne diseases and several start with
yellowing of leaves from the bottom and work their way up. Two of the most common
are septoria leaf spot and early blight. Early blight appears as spots on leaves,
stems and fruit. Leaf spots start as small, dark brown areas, sometimes with a yellow
border. Leaf spots grow rapidly under favorable conditions, forming lighter brown
bands with a dark center. Stem spots have even more noticeable rings than leaf spots
and may cause plant death if the stem is girdled. Another common disease that can
be controlled is septoria leaf spot. Spots on lower leaves usually show up as the
first tomatoes start setting and may also form on stems and branches. Spots are round,
and smaller than the early blight--about 1/8" across, with dark brown borders and
light gray centers. Young spots may be surrounded by a yellow halo as well. The disease
progresses up the plant, from the older to younger leaves, spread by splashing rain
or overhead irrigation. Fruit infection is rare. Both diseases can be controlled
with a product containing chlorothalonil- (of which there are numerous trade names
including Bravo, Daconil and Ortho’s Garden Disease control) or Maneb. The key is
not to wait to see the disease and start playing catch-up with fungicides. It is much
easier to prevent than cure the disease. Rotate your plants in the garden—don’t plant
tomatoes back in the same soil for at least three years. If you get the disease annually,
start spraying when you plant and continue throughout the season. Since you can still
harvest tomatoes with both of these diseases, you could grow the plants with proper
cultural conditions—water, sunlight, mulch and fertility and harvest what you can
until the plants play out. Then replant in a new location midsummer to have tomatoes
for a fall harvest.
(October 2008)
I have a sugar maple, ‘Autumn Blaze’ about five years old in my front yard facing
the south. It is at least 10 to 15 feet tall. I recently noticed an area close to
the bottom of the tree about 7 or 8 inches from the ground that is bleeding a black
substance. Is this usual or should I be concerned?
One of two things can be happening. Maples are notorious for “bleeding” sap from
any wound. If something wounded the tree such as a weed eater or lawn mower, this
could simply be the case and is nothing to worry about. The other scenario could
be wetwood or slime flux, which is caused by a bacteria. Gasses and liquid by-products
of the bacteria cause the internal pressure of the sap to increase, forcing the liquid
to ooze out any opening along the tree. It tends to have a sour or fermented smell
to it and is quite attractive to insects. It can be dark in color or white and foamy.
While it doesn’t signal imminent death, it does tell you the tree is stressed. Keep
the tree as healthy as possible with regular watering. Try to use your garden hose
to remove the sap from the trunk of the tree as the fermented sap can be damaging
to the trunk of your tree if left there. This problem is usually more common during
spring and summer.
(November 2008)
We have quite a few hydrangea bushes in our garden. This fall we began to notice a
few leaves developing dark spots that would enlarge on leaves and the leaves would
finally die and fall off. The leaves start with spots, then the leaves turn yellow,
eventually brown, and then they fall off. I don’t notice any insects but the plants
do not look good at all. Is there something that we should be spraying with now to
prevent this disease next season? Do you think it has killed our plants?
It is not unusual to see spotting occurring on the leaves of deciduous plants late
in the season, especially when we had as much rainfall as late in the year as we did
this year. There have also been reports that the hurricanes actually flew in some
new insect and disease problems. For now, no sprays should be needed, but do rake
up all of the fallen leaves and get them out of the yard. You may actually want to
replace the mulch under this plant as well. This way, you can start the season out
clean. I would be surprised if a leaf spotting disease late in the season would be
enough to kill the hydrangea. Monitor the plants next spring and if you see leaf
spots then, a fungicide may be called for, but not now.
(July 2008)
I have a white dogwood tree with yellow leaves falling from it. Some of the leaves
seem to have black spots and the tree looks a bit wilted. Do I need to be concerned?
I would take a sample of the diseased materials to your local county extension office.
This season we have been seeing signs of the dogwood anthracnose (Discula destructive) that is more dangerous than the small spotted form of dogwood anthracnose (Elsinoe corni) which we have had for years. Symptoms of D.destructive begin in the lower crown and progress up the tree. Leaf lesions start as tan spots
with purple rims, but can rapidly enlarge to large leaf blotches. If you do have this
anthracnose, fungicide sprays would be warranted for control, along with pruning.
Here is a link to a newsletter from our plant disease clinic with more information
on the disease complete with pictures: http://www.aragriculture.org/News/plant_clinic/2008/ten2008.pdf
(July 2007)
I have hostas and hellebores in a corner shade garden that are not doing well. Every
summer for the last 2-3 yr the hostas start to turn brown, and wilt, but do not die
completely. I was going to replace them last fall, but the root ball looked ok.
They came up this spring, but now they are wilting again. The hellebores in the same
area are finicky. A number have died, and 2 plants look good. Could this be nematodes?
Your publications talk about this with regards to crops, but not with garden ornamentals.
I am thinking of simply digging up much of the soil in this area and replacing it.
Nematodes can be in any soil and can affect ornamentals just like crops. Before you
begin removing soil, why not take a soil sample with some of the hosta roots with
it into your local county extension office. For a fee you can get the soil tested
for nematodes, and then a recommendation for control. Here is a link to our website
on how to take a sample for nematode testing. http://www.aragriculture.org/nematodes/nematode_clinic.htm
I do think that potentially there is something wrong with the site, since various
unrelated plants are struggling. However, if the root system looked good on the hostas,
then nematodes may not be the culprit. Nematodes feed on the root system of the plants
and cause stunted and/or deformed roots. I would also suggest taking a regular soil
sample in to your county extension office and see about the pH and nutrition levels.
I would also consider taking one of the hostas that is struggling in to be sent to
the disease diagnostic lab. This is a free service of our extension service. When
we have problems in the garden, you have to be a detective and cover as many bases
as possible to find out what is causing the plants to suffer.
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