Summer in central Ohio brings good times outside but also often brings hot humid air. Heat and humidity can aggravate some foliar fungal disease on trees and shrubs. One of the most common diseases we see is rhizosphaera needle cast on Blue Spruce trees.
Soil compaction is a big no-no for trees. When soil is compacted (above left graphic), water and oxygen cannot get to the vital root system of the tree. Water will collect on the surface and evaporate since it is unable to penetrate the soil. Seeing as trees need water and oxygen to live, compacted soil can quickly and severely impact the health of a tree.
If you read my first installment on this relatively new disease, you will know the major difficulty of this pathogen (Calonectria pseudonaviculata) is that it infects otherwise healthy plants, and once it is at a site, removal and destruction of the infected plants is recommended, with no plant replacement for 3-5 years. This is because the spores remain in and on the soil to infect new plants. Existing asymptomatic plants were to be sprayed with fungicides to help prevent infection.
As Central Ohio moves further into winter, and the majority of deciduous trees have dropped their leaves, bark becomes increasingly visible. Bark is an interesting and important characteristic for trees and tree identification. It doesn’t take long for a novice naturalist to distinguish certain tree species based almost entirely on the bark of a specimen (Beech, Hackberry, River Birch, etc.). Upon further inspection of a tree’s bark an observer might notice organisms growing on the trees bark. A large variety of fungi can be seen on the bark of deadwood in trees and is usually associated with poor health of that particular branch or the entire tree. However, fungi are not the only organism to inhabit the bark of trees.
I wanted to dedicate this installment to Boxwood Blight, since this is a disease which has the potential to disrupt formal landscapes all across the state. The disease is fungal, and affects boxwood, especially the cultivated varieties ‘American’ and ‘Suffruticosa’. It is relatively recent in the United States, and was found in Ohio nurseries in 2011.
Every fall I get calls from folks concerned about yellow needles on their evergreen trees. Often times I’m told that the trees are sick or that they appear to be dying from the inside out. There are some disease and insect problems that can cause yellowing and premature loss of needles in conifers but most often what people are reporting is just normal fall color.
I find it interesting that test procedures recommended in the medical field for human health have become part of the expected methodology, but not so much in arboriculture, for tree health. As arborists, we are trained that a soil test should be done prior to recommending fertilization, for example, but I don’t know of many outfits that make soil sampling a part of their modus operandi.
As we prepare for another season of Fall Tree Wellness, another important insect pest to take note of is the White Pine Weevil. White Pine Weevil is a damaging pest to a broad range of conifers, including White, Scotch, Red and Austrian pine as well as Colorado blue, Norway, and Serbian spruce. Douglas-fir can also be attacked.
Springtime is long gone, even though it only seems like a couple of months ago that we were coming out of winter. Suddenly, here we are, getting ready to enter the fall season, and true to form, during the past several weeks I have been seeing trees go into what we call “late season blues”.
“Take a look”, I said to my concerned client, as we stood in the shade of her Magnolia tree. I had just handed her my hand lens, and I showed her how to get it close to her eye as she peered through it. I wanted her to see what was in my hand – a dead adult Magnolia scale insect.
We’ve received a high volume of calls over the last couple of weeks about “bagworms” in client’s trees. In central Ohio, true bagworm feeds predominantly on evergreens - arborvitae, spruce, and junipers although some deciduous trees can be hosts as well. Generally, this
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…
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…
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…
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.
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?
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.
More and more trees are growing up in confined urban environments that force their root systems to wrap around the base of the tree causing girdling roots. Girdling roots will block vital nutrients to flow to the tree's canopy which can eventually cause the tree to die. The good news: girdling roots can be fixed if caught early!
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.
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.