Getting calls from panicked customers about black spots on maple leaves? You’re probably not alone, because now is the time when people start to notice maple tar spot. Every summer we get questions about black spots on maple leaves that look like tar. These spots are not actually “tar” on maple, but are rather a fungal disease known as tar spot. These photos show a range of symptoms presented by this disease. Tar spots on maples are caused by fungi in the genus Rhytisma. The most common species are Rhytisma acerinum and R. punctatum. Symptoms first appear in late spring or early summer as infected leaves develop light green or yellow-green spots. During mid to late summer these produce black tar-like raised structures on the upper surface of leaves within the yellow spots. R. acerinum causes larger spots that are 0.5 to 2 cm in diameter; R.punctatum causes many small[Read More…]
Archives for July 2018
Protect flowers from caterpillars through early detection and selective pesticides
Should I stake my tree after planting it? The answer is “no” for most situations, however, there are circumstances which require some support for a newly-planted tree to get it off to a good start.
On July 17th, at the Fort Harrison State Park in Indianapolis, the Natural Resources Commission passed the preliminary adoption of the Terrestrial Plant Rule (TPR) (https://www.in.gov/nrc/files/lsa18316_proposed.pdf). This rule restricts the sale, distribution, and transport of 44 invasive plants, which were determined invasive based on scientific literature by the Indiana Invasive Species Council’s subcommittee, the Invasive Plant Advisory Committee (https://www.entm.purdue.edu/iisc/plantcommittee.php). The current list was taken under advisement as those species with the greatest ecological threat. If passed through the general assembly as it is written, amendments to the rule, i.e. the addition of callery pear or others, can occur after the bill is signed into law. The Indiana Economic Development Corporation has provided an economic impact statement regarding the invasive plants rule (https://www.in.gov/nrc/files/lsa17-436_iedc.pdf), outlining the effects on small businesses. In the letter, it is noted that regulatory flexibility in potential methods for small businesses to comply with the rule. This will[Read More…]
Timing of defoliation, health, and type of tree influences the likelihood of recovery and survival
The Tree Care Industry Association (TCIA) conducted an analysis of 62 civilian tree care-related accidents reported by the media from January 2017 to June 2018. TCIA is a trade association that promotes professional tree care and discourages homeowners from taking unnecessary risks caring for their trees themselves. While these numbers are not representative of all – or even most – tree care accidents involving non-professionals, they provide insight into the types of hazards homeowners are likely to encounter while attempting tree work. The findings were grim: Forty-one of the accidents (66 percent) were fatal. “Homeowners may not realize how dangerous tree work can be, and how much they’re risking by taking the ‘do-it-yourself’ approach,” says Peter Gerstenberger, senior advisor for safety, standards and compliance for TCIA. “Lack of training, equipment or situational awareness undoubtedly contributed to these incidents, which could have been avoided by hiring a professional tree care[Read More…]
Most landscape professionals and gardeners have heard of the wise advice “leaves of three, let it be” referring to the pest plant poison ivy. While not quite as catchy, the saying really should be “leaflets of three, let it be.” Poison ivy leaves are compound rather than simple – a single leaf is divided into three separate portions, called leaflets. Plants with three leaflets are often referred to as being trifoliate. Another key identifying characteristic is that one side of a leaflet may have an irregularly toothed margin, while the opposite edge may be smooth or barely toothed. Poison ivy is typically a vine that can climb quite high by means of aerial rootlets. But older poison ivy plants, especially those that have been cut back repeatedly, can take the form of a shrub. Poison ivy flowers are rather inconspicuous and usually not noticed by gardeners. The subsequent fruits are[Read More…]
An abiotic stress in plants is a stress due to a non-living factor, such as temperature, moisture, herbicides, etc. Biotic stress includes a living organism, such as a fungi, insect, etc. This series will explore some of the most common types of abiotic stress you may find in landscapes and nurseries. We’ve all experienced the problem. Sometimes it’s barely noticeable, and other times it results in death. Even if you don’t notice, it most likely still occurred. Environmental conditions can be helpful, or quite the opposite. Of course, we are speaking of transplant shock. Transplant shock occurs when plants become stressed due to poor root establishment, often mimicking drought stress. The severity of transplant shock is dependent on many factors, which include plant species, soil type/quality, moisture, temperature, growth stage of the plant, root loss from the nursery, as well as many other factors. If transpiration rate (loss of water[Read More…]
When it comes to tree care on your property, the old adage, “you get what you pay for” applies to tree care as well. Hiring qualified arborists is important to protect one of the most valuable assets to your property, your trees.
One of the most common problems of broadleaf shade trees is a group of diseases collectively known as anthracnose. Anthracnose diseases are caused by fungi and become severe when cool, wet spring weather persists as leaves are first emerging. The most commonly affected trees are ash, white oak, maple, and sycamore. Dogwood, birch, elm, walnut, butternut, hickory, and other trees may also be damaged. Each species of tree is infected by a different species of fungus, thus the fungus does not spread from oak to maple or maple to ash or ash to sycamore. These fungi are referred to as host specific. While anthracnose diseases vary somewhat from one type of tree to another, they all cause death of leaf tissue and defoliation. Symptoms most often include irregular leaf spots and blotches (Figs 1,2,3, 4 ) The areas near veins are often most damaged and can lead to curled and[Read More…]