Verticillium Wilt

It’s hard to miss this disease once we enter the hot dry months of summer.  Without fail, each July/August I start to see trees turning brown and wilting suddenly, usually in patches within the canopy that can be traced back to entire individual limbs that have died.  More dramatically, an entire tree will just turn brown and wilt. The pattern of wilting is very regular, and the symptoms can carry over into winter because the wilted leaves sometimes stay on the tree well after normal leaf drop in the fall.

Verticillium Wilt (VW) is easily recognizable once you know what to look for, but not easily treated.  To make matters worse, it affects a large number of trees and plants, with varying expression of symptoms from tree to tree.  During my years as an arborist, I have found Norway Maple, Japanese Maple, Yellowwood, Smoke tree, Redbud and Magnolia to be very common hosts of this disease.  And this is a short, short list of the plants that can be affected.  

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Dead Sugar Maple, suspect VW due to suddenness of wilting

The disease is caused by a fungus present within the soil, and there are so many ways it can get into the soil that my approach is usually “if there is soil present, there is probably VW present”.  What do we do? It sounds like a copout, but the best answer for dealing with this issue is the best answer for dealing with most plant pests and diseases: Choose the right plant for the site conditions. This is the best way to cultivate healthy plants that can naturally cope with the more problematic neighbors within an ecosystem. But this doesn’t really help the tree that has already been planted and is making do with what it has.

If the tree has already been planted, the next best option is to do everything possible to manipulate conditions at the planting site to minimize stress factors to the tree. Ensuring proper moisture, adding organic mulch matter, amending soil both chemically (fertilization if needed) and physically (soil aeration/relief of compaction) are all good measures that can be taken.  There are systemic fungicides that can be applied to suppress the development of the disease within the vascular system of the plant as well, but these applications should be secondary to the site work.

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Dead vascular tissue in Sweetbay Magnolia characteristic of VW

The fungus can enter the tree by wounds in roots but can enter roots even when no wounds are present. Once in the tree, the disease tends to progress upward and outward, causing foliar wilting and dieback to varying extent.  I have seen trees coexist with the disease for years and years, seemingly keeping up with the disease, losing a branch here and there, but generally coping with it. On the other hand, I have seen trees decline quickly. I recall one Sugar Maple which barely had any symptoms until it wilted from head to toe and died over the weekend.

In closing, I feel that VW is an example of how trees really die. There are questions that need to be asked, such as “Was it just a super-virulent strain that entered the tree?” or “Was it a weaker strain, but the tree was just weakened by multiple other factors?”. Sure, there may be cases where everything is perfect for the tree, but the disease was like The Terminator -  unstoppable. In my experience though, most trees die because something else has made them vulnerable and weak enough that a relatively low-grade disease is what finishes them off.  In that case, treating the disease is a last-ditch effort that can only really work if the treatment keeps the tree alive long enough to benefit from the effects of cultural changes that should be implemented if possible.

I think there is a life lesson that can be applied here, but I will let the reader sort that out. Have fun out there!  For every wilted leaf, there are 100 other green ones.

Your friendly neighborhood arborist, 
José Fernández
ISA BCMA® OH-5129B

The Importance of Green Leaves

Chlorosis in a River Birch causing a die-back in the canopy

I have been noticing what I consider to be an unacceptable amount of chlorosis in urban trees around Columbus. In general, chlorosis is the yellowing of plant foliage caused by a lack of chlorophyll. This is a problem because plants depend on chlorophyll to absorb energy from sunlight and to survive.

Several factors can contribute to the development of chlorosis in trees such as nutrient deficiency, drought, poorly drained and compacted soils, girdling roots, graft union incompatibility and mechanical damage to the tree trunk. For the purpose of this article, I’m going to focus on chlorosis caused by nutrient deficiency because I believe it’s the most prevalent and most often mismanaged. Although any nutrient deficiency could lead to chlorosis in trees, manganese and iron deficiency is what we see most.

Chlorosis in a Red Maple

Chlorosis in a Pin Oak

It is important to understand that the availability of nutrients from the soil can vary with soil pH.  For example, even though there may be an adequate amount of manganese for a certain tree in the soil, the soil pH can cause the manganese to be inaccessible by the tree. Most urban soils in central Ohio are alkaline. (A quick review for those of you who fell asleep in biology, the soil’s pH is an indicator of soil acidity or alkalinity. On a scale of 1-14, 7.0 is neutral, below 7.0 the pH is acidic, above 7.0 the pH is alkaline. Nutrients are most available to trees when the soil pH is between 5.0 and 6.5. Because most of our urban soils have a pH of around 7, we find ourselves dealing with chlorosis.

Initially, chlorosis expresses itself in the canopy of trees by the yellowing of foliage with a network of green veins.  As the chlorosis progresses, leaves become a paler yellow and develop brown necrotic lesions. Leaf margins will eventually brown completely and leaves will dry up and fall off.   Over time this results in poor vigor, reduced twig extension, poor density of canopy, dieback and eventual tree death.

The easiest way to manage chlorosis is to prevent it by planting urban tolerant trees that are tolerant of high pH soils. Although most trees species have the potential to develop chlorosis, the most common trees affected by high pH soils in central Ohio are Pin oak, Red maple, River birch, Shingle Oak, Red Oak, Sweetgum, White pine, and Canadian Hemlock. If you notice yellow leaves on your trees (and it is not time for Fall color) it is important to take action for long-term preservation. 

Russell Tree Experts Tree Wellness Technician Collecting a Soil Sample

The first step is to have a soil and plant tissue test performed. This is the only way to know which nutrients are lacking in your trees and soil. Any attempt at correcting chlorosis without the information from these tests is guesswork and treatment without proper diagnosis is malpractice. We can have these tests performed for you,  interpret the results, and determine the best management for your tree(s).

Just another way Russell Tree Experts is keeping Ohio green!

TJ Nagel
ISA CERTFIED ARBORIST® OH-6298A

Black Knot Disease In Plum & Cherry Trees

Black Knot is a relatively common disease that mainly effects Plum and Cherry trees, but can impact other trees in the prunus species as well. These types of trees can frequently be seen growing in and around Columbus area neighborhoods. Black knot is actually a type of fungus (Apiosporina morbosa). Its characteristic look consists of irregularly shaped black outgrowths arising from tree branches. It often spreads in the springtime but is not noticed by homeowners until winter after the tree leaves have fallen. If left untreated, the black knot growths eventually expand and encase the limbs and twigs of trees and can lead to dead branches, even death of the tree itself. Unfortunately, by the time many homeowners identify this as an issue, the fungus has already critically damaged the tree.

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Early Stages of Black Knot in a Purple Plum Tree in Blacklick, Ohio

It’s best to catch this disease early as this is when it is most easily treated. An early warning sign that black knot may be affecting your tree is the presence of small green swellings/growths on a tree's branches. The first step in treatment is the identification of the presence of the disease. Once identified, selective sanitary pruning of the tree in combination with a fungicide can be instituted.  Unfortunately, if the tree is in the advanced stages of the disease, these treatments may not be enough and the tree may need to be removed. In summary, Black Knot is an important disease that is relatively common, especially in trees types found throughout the Columbus area and is best treated when caught early.

Chris Gill
ISA CERTIFIED ARBORIST® OH-6416A

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If you suspect that your tree(s) may be infected with Black Knot, feel free to give us a call 614-895-7000 or request a free quote!

Witch-Hazel Cone Gall

The photo below is of Witch-hazel cone gall, caused by an aphid bearing the same name.  I find insects that cause galls to be really interesting.  There are many different types, usually host-specific, with various shapes and sizes of galls formed.  In most instances, the feeding of the insect causes an abnormal growth reaction in the plant that forms this gall where either the adult or the immature insect lives inside.  In this case, a single aphid will feed on the leaf in spring, causing the gall to form.  While inside the gall, the female aphid will produce young that eventually emerge in two forms, with two destinies: A wingless form stays on the host plant; the winged form goes to live on Birch trees.  In autumn a second winged generation develops and flies back to the witch-hazel where eggs are laid on the twigs to start the process again the following spring.

Cone Gulls in a Witch-Hazel Tree

When we see galls on leaves and twigs, do we stop to think about the lives of these insects, and the plants that support them?  This world we share is much larger than we realize – it gets bigger the more we look up, or down, and we’re all in this together.

Your friendly neighborhood arborist,

José Fernández
ISA BCMA® OH-5129B

Insect notes summarized from Insects That Feed on Trees and Shrubs, by Warren T. Johnson and Howard H. Lyon, second edition.

Fire Blight is No Delight

A Crabapple tree infected with Fire Blight

Fire Blight is No Delight

As an arborist, I can spot spring coming in February when a faint reddish tinge starts to color the woods.  This tells me trees are starting to stir, and warmth will soon be on its way.  Despite the early clues that I am looking for, I am always amazed by the vibrancy of life once trees have fully emerged.  Yes, I love the stage when trees are flowering, but somehow once trees are fully leafed out they look so alive, so perfect, so unblemished.  No bugs, no drought stress, no fungal diseases – just full, green leaves.

And then… pests and pathogens let us know that they have been waiting for spring as well.  What can we say?  Life the way we know it is varied and expressed by many different forms, each trying to survive in its own way.

The "Shepherd's Crook" - a sign of a tree being infected with Fire Blight

This year has been a particularly bad one for fire blight on Pear and Apple trees.  Fire blight is a bacterial disease that affects plants in the Rosaceae family, causing a characteristic blackened wilting of leaves and twigs. This family of plants is also popular for its landscape value, both for flowers and fruit production. Pear, Cherry, Rose, Apple, Serviceberry, Cotoneaster, Hawthorn are just a few trees and shrubs that are very familiar to us. Have you noticed a profusion of dead, blackened leaves in your neighborhood? In your trees?

There are ways to stave off the progression of the disease, even now. Ideally, the trees would be treated earlier in the season for better control, but a combination of steps are recommended for trees that are highly susceptible to the disease. Treatment steps vary depending on how affected your tree is.

Thanks for being our client, and for loving your trees! I’ll see you out there.

Your friendly neighborhood arborist,

José Fernández
ISA BCMA® OH-5129B

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3 Tips to Check for Fire Blight

1. Check if your tree's leaves are browning only at the tips of the limbs
2. Check if limbs have the "Shepherd's Crook" (FYI - The Shepherd's Crooks doesn't always occur in trees infected with fire blight but it an obvious sign of the Fire Blight inspection.)
3. If you suspect your tree has fire blight, please click here or call 614-895-7000 and we'll send a Certified Arborist to review the tree and give you a quote to treat the issue

Watch out Crabapples! Apple Scab is a Major Threat!

As seen above, apple scab produces lesions on leaves, flowers, fruit and on young succulent shoots. (photo courtesy of Wikipedia)

Plant diseases love Spring! As temperatures warm and tender new growth emerges, conditions are ideal for pathogens to settle in and take up residence in our favorite trees. It is now when many plants are susceptible and treatable for diseases, such as Dothistroma needle cast of Austrian Pine, Rhizosphaera needle cast of Blue Spruce, rust diseases on hawthorn and pear, and for the purpose of this article: the aesthetically devastating apple scab on flowering crabapple.

What is apple scab and what does it do?

• Apple scab is caused by the pathogen Venturia inaequalis.  It is a common disease targeting the rose family of plants which includes crabapple, apple, pear, hawthorn, mountain ash, cotoneaster and pyracantha.
   
• Apple scab produces lesions on leaves, flowers, fruit and on young succulent shoots.  When infected areas are numerous, leaves can become curled and distorted and severe infections can lead to complete defoliation of trees and shrubs.
   
• Several years of early leaf loss generally results in poor growth, reduced bloom and increased susceptibility to winter injury and insect predation.

How does the disease work?

• Apple scab overwinters in fallen diseased leaves and in the soil.  Disease development is favored by wet weather and cool temperatures that generally occur in central Ohio in the Spring and early Summer.  Fungal spores are moved from the ground and carried to trees by raindrop splash and wind where they make their way to leaves, flowers, and fruit.  
   
• During wet periods, newly emerging crabapple leaves are extremely susceptible to infection.  The longer the leaves remain wet, the more significant the infection can be. 10 - 20 days after initial infection, new spores are released which infect new leaves.  Repeated infections can continue through the summer until environmental conditions become too hot and dry for the pathogen.

What can be done to protect my crabapples?

• For most cultivated varieties of crabapple, fungicides must be applied preventatively to successfully manage apple scab.  Fungicide sprays should begin when the first green leaf tips are emerging with additional sprays being applied in roughly 2-week intervals.  The number of fungicide applications needed can vary with weather conditions but generally, we recommend 3 separate applications.
   
• Other cultural practices that can increase the effectiveness of fungicide applications when managing apple scab are:

1. Raking up and destroying fallen leaves to reduce locations where the apple scab pathogen can overwinter
2. Space crabapple trees generously to increase air circulation around trees
3. Prune out crossing limbs, vigorous upright sprouts and suckers to increase airflow and sunlight penetration into the canopy (this can help foliage dry faster after rain or dew)
4. Avoid overhead irrigation, if plants need water, apply water directly to the root zone.

Additionally, much breeding and selection work has been performed to introduce scab resistant crabapples into the landscape.   A short list of some of the most resistant cultivars includes:

• Coralburst
• Donald Wyman
• Prairiefire
• Purple Prince
• Red Jewel
• Royal Raindrops
• Sugar Tyme

Other common fungal diseases of plants that can be managed through the use of our fungicides include:  Oak Wilt, Dutch Elm Disease, Powdery Mildew, Anthracnose and Verticillium wilt. 

Are Your Trees Being Suffocated By Their Own Roots?

Please note: This article was originally published on 3/28/2018 and was republished on 3/25/2021.

Unfortunately, more and more trees are “growing up” in unnatural environments that force their root systems into confined spaces which leads to the formation of girdling roots. From the start of a tree’s life, girdling roots may be forming. Trees grown in nurseries are forced to grow in small containers. This practice encourages the binding and tangling of roots AKA pot-bound. Poor nursery practices and poor planting practices are the two most common ways girdling roots are introduced into landscapes.

Other “tight spaces” include trees planted near homes, backyard structures, sidewalks, or roads. Even a perfectly placed tree can fall victim to girdling roots by the act of over-mulching its base –a trend that has resulted in the death of many trees by many well-intentioned homeowners

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Four Signs of Girdling Root Issues

1. The tree appears to be dying from the top down
2. The tree is late to leaf out in the spring and/or has smaller than normal leaves
3. There are visible roots above the surface circling the trunk:

4. There is no visible root flare:

Good - Root flare is above ground

Bad - Root flare is below the mulch

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Why do Girdling Roots Form?

In an attempt to survive, the trees root system branches out in search of nutrients, only to be blocked by nearby structures and are forced to re-direct backward onto themselves, serving as a tourniquet –cutting off the nutrients the tree was so desperately in search of. Root collar excavation serves to identify these “problem roots” before they cause permanent irreversible damage.

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How We Fix The Problem

Root collar excavation is a technique used to expose “problem roots” that may be suffocating your tree and cutting off vital nutrient uptake, ultimately leading to the demise of your tree. These “problem roots” are known as girdling roots. Girdling roots are roots that tightly wrap themselves around the base of a tree in an unnatural fashion. A tree root collar (AKA tree root flare) is the area where the first division of roots attaches to the trunk of the tree and is the area where girdling roots form.   

Root collar excavation is a process that involves directing high-pressure air at the base of the tree to displace local soil in order to inspect the root system. Once problem roots are identified we begin the process of careful and selective root pruning to remove the unwanted roots while keeping the tree healthy and vigorous.

Step 1

Review the tree to see if any visible roots are wrapped around the base of the tree. Another symptom of girdling roots is die-back starting in the top of the tree.

Step 2

Using an AirSpade, the soil will be blasted to expose the tree’s root system below the surface. Don’t worry, the AirSpade only moves the soil and does not hurt the tree and it’s fibrous roots.

Step 3

The arborist will then identify all the girdling roots and remove them using hand tools and/or a chainsaw.

Step 4

The root zone is then covered with composted mulch and voila! - the tree can “breathe” again!

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Contact Russell Tree Experts for Help!

It may be hard to identify girdling roots on your own tree so if you have any questions, our certified arborists at Russell Tree Experts will be happy to inspect your trees. We can perform root collar excavation year-round but we recommend doing this in early spring or late fall as it is healthiest for the tree.

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How to Avoiding Girdling Roots

1. Avoid over-mulching! Avoid those mulch volcanos.

2. Plan ahead! Pick your planting site wisely, use proper planting practices.

3. Choose tree species wisely! Some trees are at higher risk of developing girdling roots (ie: Maple, Crabapple, Cherry, and Pear trees).

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Neonicotinoid Use in Ornamental Landscape and Effects on Honeybees

Neonicotinoids are chemical products that are effective in systemic control of insect pests in plants.  Systemic application of insecticide has multiple advantages over other methods, such as topical applications.  When applied systemically, neonicotinoids are absorbed by the plant, and persist for a longer period of time, so that insect pests subsequently feeding on plant parts ingest the chemical and die. 

Because of this mode of action, there has been concern about neonicotinoids persisting long enough to be found in plant products such as nectar or pollen, where they could be ingested by foraging bees.

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I have been following this topic for several years, collecting various articles that have been trickling in.  As licensed commercial applicators, we are trained that “the label is the law”, so pesticide applications to plants are always made according to label instructions.  However, there have been claims made about neonicotinoids causing problems for Honeybee populations.

I have personally attended seminars here in Ohio where scientists leading research on neonicotinoid use for controlling invasive insect pests have stated that despite some claims to the opposite, there have been “no documented studies” proving a relationship between neonicotinoid use and Honeybee decline.  Since then I have read some articles referring to studies that seem to show a correlation, but no conclusive proof.  As an applicator who cares about the welfare of beneficial insects, the lack of conclusive studies is a source of frustration.  In fact, the approach I was leaning toward was “if there is a high level of uncertainty, perhaps it is best to seek alternatives for treatment, or to not treat at all”.  There is a lot to consider when deciding whether or not to treat a plant chemically, but that topic is beyond the scope of this article.

What is the issue with neonicotinoid use and bees?  The reason neonicotinoids are great options for pest control are ease of application, larger windows of application timing, and more targeted applications.  Using topical sprays to control pests requires very specific timing (pest usually needs to be present at the time of spray), and there is a risk that other non-target plants may get sprayed (wind drift).  Also, non-targeted insects present at the time of application can come into contact with the chemical.

A systemic application is much simpler: no spraying may be required (usually applied as liquid drenches into the soil around the root zone of the target plant, or injected directly into the tree), only insects feeding on plant tissue are targeted, and timing is much less critical since the chemical resides within the tree, eventually breaking down so reapplication is necessary for continued control.  And this is the question raised by many concerned people: If the plant tissue has enough chemical to kill insects feeding on the plant, isn’t it possible that the nectar produced by the plant’s flowers will be laced with the chemical as well?  So how does this affect bees?  These are very reasonable questions, and I agree that they merit consideration.

I was intrigued to see Bernadette Mach (Department of Entomology, University of Kentucky) on the speaker schedule at the Ohio Chapter ISA Tree Care Conference in Columbus, Ohio, this year.  Intrigued, because she was speaking on the topic of neonicotinoid levels that persist within a plant after treatment, specifically in nectar.  Her talk was in two parts, both of which applied to our concerns as commercial applicators.  The first half dealt with her studies on which flowering plants were attractive to bees.  The second half was measuring residual levels of systemic chemicals in nectar following application at label rates during different times of the year.  Details of her study informing the second half of her talk can be found online (Uptake and Dissipation of Neonicotinoid Residues in Nectar and Foliage of Systemically Treated Woody Landscape Plants). 

In short, there were several important details that I came away with:

1. Of two chemicals commonly used, one has a lower residual in nectar than the other.
2. The timing of the application matters.  Applications made post-bloom had a low residual in nectar the following year.
3. For some plants, the issue does not matter.  For example, Boxwood, in particular, has caused me difficulty.  Leafminer is a very common insect pest that can destroy Boxwoods, but it can be readily treated with a systemic application.  Last season I began communicating with clients my concern over treating Boxwoods and potential harm to bees.  After communicating with Bernadette specifically on this topic, I feel more comfortable continuing with Boxwood treatments as usual.  The reason is that Boxwoods are not a plant that attracts bees, so there is a greatly reduced risk that they would feed on the nectar.

As a Certified Arborist and licensed commercial applicator making recommendations to clients, I need to consider each plant prior to treatment.  Yes, the client wants to control Magnolia Scale, but should we attempt to do so systemically?  Is this plant attractive to bees?  If so, should we time the application post bloom?  Will this concur with the insect life stage being targeted?  What about other options?  Can we apply a targeted topical spray that will be effective?

In some cases, nothing more will be possible than to explain to the client the implications of treatment.  For example, if the client has a Hawthorn that consistently looks ugly each season when the leaves turn brown and blotchy due to Hawthorn leafminer, I can explain that the best way to control this pest is with a systemic application in the fall (which is essentially pre-bloom) to protect the tree from the pest in spring.  This means that there will be higher levels of neonicotinoid in the nectar the following spring, and since bees are attracted to Hawthorn blooms there is a chance they may be affected by the chemical.  Leafminer in Hawthorn causes damage that is mostly aesthetic.  Once the client considers all this, she may simply choose to leave the tree untreated and deal with some less than perfect leaves. 

Ultimately Certified Arborists that are licensed commercial applicators will be making applications based on label recommendations provided by the specific chemical manufacturer.  However, we need to follow the thought process outlined above to make responsible decisions, understanding that our choice of which chemical to use when to apply it, and how to apply it may have effects that reach further than simply trying to save one plant, or make it look better.

José Fernández
ISA BOARD CERTIFIED MASTER ARBORIST® OH-5129B
ODA COMM. PESTICIDE LIC. #105859 (Categories 2B, 4A, 6A, Core)
TREE RISK ASSESSMENT QUALIFICATION (TRAQ)

Poplar Weevil

On Monday, June 11th, TJ shared some leaf samples he had collected in the field. These leaves were marked with feeding damage from a small black insect he also had collected to show us. I had never seen or heard of this critter before that day, but TJ's sharing could not have been more timely. Since then I have had the opportunity to see evidence of plant damage by the Yellow Poplar Weevil from Ostrander to New Albany.

Here at Russell Tree Experts we have had an ongoing conversation about how to treat this pest, and if treatment is necessary. I did a little research initially and confirmed what TJ had shared with us: the insect has only one generation per year, and the damage to the leaves of Tulip Poplar, Magnolia, or Sassafras trees is mainly aesthetic and does not require treatment. This is to be contrasted with a spider mite infestation, for example, where multiple generations can cause a huge outbreak in a short period of time causing great damage to a plant.

This information was consistent with what we found in the field that week. The following week everything changed, when TJ and I went out to inspect a young Tulip Poplar that had been in the ground for about a year. From a distance my first thought was that the tree had not been watered, for every leaf except a few in the inner canopy looked completely brown and dead. When we walked up to the tree we were amazed to find the largest population of Yellow Poplar Weevil we had seen to date. They were so numerous that the adult feeding damage had almost completely browned out the leaves. As TJ went for the garden hose to try to spray the weevils off, he realized his fluorescent green Russell Tree Experts T-shirt was covered in weevils. They either liked his shirt or his aura (or his odor?) because I was left out of this meeting between arborist and insect. This was good. Not so good when TJ helplessly let out a yelp when one of the weevils bit him on the back of the neck. This was something our research had not warned us about! But as I look back I think the bite was friendly. Or romantic.

After we realized the hose was not going to get rid of the clouds of flying adults, we made the decision that with serious outbreaks like this one, the best thing to do was to apply a topical spray to kill off the adults. This we would follow up with an application of a systemic insecticide next spring labeled for weevils in case we should have a second outbreak next year.

Presently I think the damage has been slowing down as adults prepare to descend back into the duff at the base of the trees. I have been an ISA Certified Arborist for 9 years in the Columbus area and this is the first year I encountered this pest. Indeed, TJ told me he had spoken with a couple of older arborists who remembered an outbreak "around 20 years ago", and "a long time ago".

Here is a helpful link to read up on the insect if you have been seeing this in your landscape:
http://bugs.osu.edu/bugdoc/Shetlar/factsheet/ornamental/FSyellowpopweevil.htm

Points to Remember:

• IMPORTANT: Though TJ claims he was bitten, these insects are not known as biting or stinging insects. I have handled them many times, had them drop onto me from trees, and have never suffered any harm. TJ's experience was special. Weevils are not really evil. Or romantically inclined.

• Only one generation per year, so what you have now is all you will get.

• Damage is usually minimal, and does not require treatment.

• If population is high for your plant, a topical spray is recommended to kill the adults. Spring follow up with a systemic may be recommended in case we have another outbreak next year.

Call Russell Tree Experts for any questions related to this or any other issue with your trees!

Imprelis damage on pines and spruces

I’ve recently responded to several clients who needed an ISA Certified Arborist to evaluate their trees for Imprelis damage.  In cases like this, it is easy to walk up to a tree such as a  White Pine or a spruce, see the familiar symptoms of Imprelis damage from a distance and make the conclusion that Imprelis was the culprit causing the dead, curled stems at the top of the canopy.  

This is a prime example of having to set aside preconceived ideas about what may be wrong with a tree.  First, the thought of Imprelis has been introduced by the client, which tells me that Imprelis has been in use at the property.  Second, the tree in question is a tree known to be susceptible to Imprelis damage. Third, as I approach the tree the symptoms look like Imprelis.  As an arborist, I have to slow down, set aside the preconceptions, and look closely at the tree, as White Pine Weevil (WPW) is another common problem to pines and spruces that causes symptoms somewhat similar to those caused by Imprelis.

During the past two weeks, I have had the above scenario play out in 3-4 instances, enough times that I thought it worthwhile to write about.  Though the symptoms and the host trees are similar, there are some differences worth pointing out:

1. With Imprelis damage, the affected tips are usually spread throughout the canopy. With WPW usually only one stem (sometimes more) will be affected, and this will almost always be the top stem in the tree. However, I have seen trees lightly damaged by Imprelis that showed symptoms on only one or two stems, and those were in the top of the tree as well.
   

2. Imprelis typically causes unnatural swelling of buds and stems. Not so with WPW.
   

3. WPW can cause a distinctive sap flow which can be seen from the ground if present.
   

4. If the culprit is WPW, careful inspection will reveal exit holes coming from the damaged stem of the tree. If it is possible to prune the dead tip out to make a close inspection, signs of WPW will be unmistakable if that is the culprit.

I have seen one spruce with light Imprelis damage that also  had WPW.  This needed to be taken into account so both problems could be addressed in the diagnosis.

Moral of the story?  Approach every tree, every client, every person, with a blank slate.  It is easy to look at trees and people with preconceived notions getting in the way of an accurate and fair appraisal, and people, like trees, do not respond well to incorrect treatment.

Your friendly neighborhood arborist, 

 José F.

Asian Longhorned Beetle

In August of 2012, Joe Russell, TJ Nagel and José Fernández made a trip down to Cincinnati to hear Joe Boggs,  entomologist and OSU Extension Educator in the Cincinnati area, give a talk on Asian Longhorned Beetle (ALB).  Following are some quick facts from lecture notes and from www.beetlebusters.info presented as FAQs:

Q: Where does ALB come from, and is it in Ohio?
A: ALB is native to eastern Asia, specifically to China and the Koreas.  Interestingly, it was introduced to Japan, but was successfully eradicated. ALB was first reported in Ohio on June 17th, 2011 in southwestern Ohio, Clermont County.  Based on DNA testing, this infestation came from Asia, and is unrelated to other infestations in the United States.  We do not know how it came to Ohio.

Q: How long has ALB been in North America?
A: ALB has been in North America since 1996, where it was discovered in Brooklyn, NY.

Q: What areas are quarantined in Ohio, and what does this mean?
A: Regulated materials, including firewood, stumps, roots, branches, debris and other material –living, dead, cut, or fallen- from all hardwood species, nursery stock and logs of ALB host trees cannot be moved out of a regulated (quarantined) area.  The Ohio Department of Agriculture (ODA) has established three regulated areas within Clermont County and will continue to update the status of these areas as needed. 

Q: What trees are at risk?
A: Very good hosts, in order of pest favor, are all maples, horse chestnut, elm, and willow.  However, the beetle will attack 13 different genera of trees, including all species within the genera.  Some other common trees that are vulnerable are birch, sycamore, poplar, mimosa, and hackberry.

Q: General eradication (at the forest level) of Emerald Ash Borer (EAB) was a goal that proved to be expensive and sometimes unachievable.  How can we say ALB can be contained and eradicated?
A: EAB and ALB are very different beetles, both in their rate of reproduction, ability or desire to spread and feeding habits, among other things.  To be considered eradicated, no beetles can be found within a period of three years in a zone that was previously infested.  This requirement has been met in Chicago, IL, Hudson County, NJ, and Islip, NY.  Currently, there are other locations in NY and NJ that are undergoing eradication, as well as Massachusetts and Ohio. As for EAB, eradication on a large scale is not practical, but there are several proven methods that arborists use to successfully protect individual Ash trees from infestation, even where pest pressure is very high.

Q: What does the beetle look like?  What do I do if I think I found one?
A: I found the Chinese name for ALB to be a good way to remember how it looks.  In China, ALB is called “Starry Night Beetle”, because it is black with irregular white spots on its back.  It has very long, black and white banded antennae, and is a large beetle, measuring 1 to 1 ½ inches long.  Another way to spot the beetle is by their activity.  Look for perfectly round, nearly dime-sized exit holes in trees, with noticeable amounts of sawdust (frass) built up on the limbs or on the ground.  Limbs weakened by the large exit holes can break readily in a windstorm as well.

If you spot one, call Russell Tree Experts for one of our arborists to come out and make an inspection, or go to beetlebusters.info for more information.

Q: Can ALB be controlled without destroying the tree?A: Due to lack of space, I cannot go into details here.  It may be controlled, but there is difficulty due to the different feeding habits in each developmental stage.  Currently, a tree found with ALB will be cut down and destroyed.  The beetle is considered to be one of the most destructive and costly invasive species ever to enter the United States.

Forest Service Report to congress:
http://www.fs.fed.us/aboutus/budget/requests/DDBR428_Emerald_Ash_Borer_report_to_Congress.pdf

APHIS Fact Sheet:
http://www.aphis.usda.gov/publications/plant_health/2011/fs_ohio_regulated_area.pdf

How to Water Your Trees

How do I water my new trees?

Believe it or not, there is more to watering a tree than simply spraying it with a hose once in a while.  Properly watering a tree will ensure that the tree establishes well at its new location, developing strong, deep roots that will sustain it through periods of drought as it matures.  Please note that this article will not deal with how to properly plant a tree, although how the tree is planted does influence how water enters into the root zone.  

First of all, you need to know what type of soil you have.  In central Ohio, heavy clay soils are most common, and almost guaranteed if you live in a newer housing development where the soil structure is far from normal due to common construction practices.  If you happen to have a sandier soil than commonly found in Ohio, you will need to adjust your watering accordingly.

A few things to keep in mind:
1. Roots grow where there is water and oxygen
2. Roots, and therefore trees, do best when moisture levels remain constant.  Moisture does not mean saturation.
3. When you water a tree, water will infiltrate the soil, percolating through the soil profile as it drains through.  This drainage is essential for proper oxygen levels to remain in the soil.

Newly planted trees lost a large part of their root zone when they were dug at the nursery to bring them to your landscape.  Because of this, maintaining proper moisture levels is essential.  As we want to encourage deep root growth, we need to get the water down to the bottom of the root ball.  To do this, slow watering is required to allow the water to soak into the soil without running off.  

The method I prefer is using a soaker hose looped around the root zone of the tree.  I monitor moisture levels every couple of days and run the soaker hose for a couple of hours if needed. More for larger trees. In cooler weather, such as spring and fall, watering will be less frequent.  In hot, dry summer weather, watering will be more frequent.  I hesitate to tell folks to water "every 2-3 days" or "once per week" because I don't want to add water when it is not needed.  Such rules of thumb are not necessarily bad, because at least regular watering takes place, but monitoring moisture has worked well for me.

Run your soaker hose until you are sure the soil is saturated.  Then do not water until the soil begins to feel dry to the touch.  Don't wait until it is bone dry before you water again, just seek to maintain decent moisture.  The cycle we want to maintain is one of saturation, drainage and beginning to dry out before beginning the cycle again.

Why not water a little bit every day?  Isn't this the same?  The answer is no.  Watering a little each day only waters the surface roots.  The tree will survive, but may not establish roots down deep where it can find moisture during droughts once it has established and you will probably not be watering daily.  For this reason I do not recommend counting on a lawn sprinkler system to sufficiently water a new tree.  Go with the soaker hose method or use those green bags and make sure you fill them as needed.

You should water as described for the first three seasons, and then as needed after that.  It is easy to forget to begin watering in the spring.  Some springs are drier than others, so don't forget to start checking moisture early.  I also continue watering in the fall after the leaves have dropped (if the tree is deciduous) because there is a period of root growth between leaf drop and true dormancy that I want to help along as much as possible.  A tree going into winter dormancy under drought stress will not make it through the winter very well.

Remember: slow, deep, infrequent watering does the trick.  Allow the soil to drain and begin to dry before watering again.  If your site is poorly drained, keep in mind the bottom of the root ball will dry more slowly than the top.  We do not want to keep the roots waterlogged as this will kill the tree.  
Generally, if there has been 1"- 1.5" of rain per week you will not have to water unless your tree is planted in a place where water runs off too quickly to infiltrate the soil.

Remember, you can always call the office and ask for the Certified Arborist who serves your area if you have any further questions about planting or watering.

Thanks and good luck!

Your friendly neighborhood arborist, 
José Fernández

Oak Wilt in Franklin County

Several weeks ago a client called the office about some Red Oaks that were dying, one by one. I arrived at his home in north Columbus and he quickly filled me in on the details: Two years ago one tree died, last year one other tree died (neighbor’s tree nearby) and this year two more trees had died.

After inspecting the site I found the mature Red Oak were within about a 50’ diameter area, and were all defoliated. One tree still had some dead leaves attached to limbs high in the canopy as well as some sprouts in the inner canopy with a few remaining green leaves. The site was a nice stand of native woods surrounding a ravine area that spans across the rear of multiple properties.

I inspected the base of the tree and found some weeping spots at the base of the trunk on two of the trees:

There were a couple of areas with vertical cracks oozing black seepage. These symptoms, coupled with the fact that the trees had died quickly, brought a couple of ideas to mind, but I wanted to sample the trees and send them to the lab for a proper diagnosis as all the things I was thinking of were very serious. The client had done some research on his own and suspected Oak Wilt. I had not heard of this in our area, although I was aware that this is a problem north of the Columbus area.

Samples were retrieved from the middle canopy, selecting two branches that had both dead and live leaves in hopes that a transitional section could be sampled. After several weeks, the C. Wayne Ellett Plant and Pest Diagnostic Clinic (The Ohio State University) was able to identify the fungus Ceratocystis fagacearum which causes Oak Wilt.  

Please follow this link for the Ohio State University Extension Fact Sheet on Oak Wilt, where the information summarized below is drawn from.

The implications of this are serious. All oak varieties are susceptible, and Red Oak seem to be particularly vulnerable.  

The disease can be spread both by root grafts (roots from neighboring trees growing together) and by sap feeding beetles and possibly oak bark beetles. Because it spreads in two ways, two approaches are needed to stop the spread of the disease.

The beetles that are vectors for the disease area attracted to fresh wounds on Oak trees, so pruning of Oaks during the growing season when the beetles are active is not recommended. A pruning wound will attract these beetles, and if they have been feeding on infected trees, the healthy trees will be subsequently infected.  

To prevent infection from tree to tree, trenching between trees is recommended to sever any root grafts. This is not always feasible depending on soil type and tree location, and trees must be accessible with proper equipment.

A fungicidal trunk injection can be applied preventively to healthy trees in order to help protect them from infection. The treatment needs to be reapplied every one to three years in order to maintain its efficacy.

In Closing: I have an Oak tree. What does this mean for me?

1. For maximum safety, do not allow your tree to be pruned during the growing season when beetles are active.  
2. If your tree is a vital part of your landscape, consider a trunk injection to increase the odds it will not be infected.
3. If your trees are infected and need to be removed, make sure the Certified Arborist doing or directing the work knows how to dispose of the material to prevent spreading the fungus.

Ask An Arborist: Can I save my ash tree?

@mikeresa: 
Is it possible to save a young Ash tree from the Ash Bore?

José Fernández ISA Board Certified Master Arborist, Russell Tree Experts:
Yes, it is very possible. There are many methods of treating Ash trees for Emerald Ash Borer (EAB), but experience has proven that there are two methods that work best:
Soil drench method and trunk injection method.The trunk injection method is recommended for trees that have an existing infestation. The soil drench method works well as a preventive measure to maintain resistance on healthy trees. It is important to have an ISA Certified Arborist inspect the tree in question to determine if it is a good candidate for treatment.
 
We are proud to have a very long list of clients with Ash trees that have remained healthy through the worst of the EAB infestation in central Ohio, and we have seen infested trees come back to health over several treatment cycles.