Tree Disease Prevention Service in Scarborough

Trees are living and breathing things and like all living things sometimes get sick. However, with the proper diagnosis, treatment and expert arborist advise, in a large number of cases we can bring them back to life. Quite often, homeowners are unaware that their trees are in fact diseased and infected. Below are common tree diseases found in Ontario.

Emerald Ash Borer​

A jewel beetle that is commonly known as EAB, it originally came from East Asia and possibly shipped along with wooden materials to the American continent. This beetle, specked in metal-green, along with their larvae stages, has harbored decimation to ash trees in the millions. Noticing the signs for EAB in trees requires visual acuity including the ability to detect wilted & thin leaves, exit holes forming a D-shape, woodpecker-like borings, and bark tunneling. Reporting EAB presence to the nearest agricultural governmental institute can help remedy the proliferation of the pests. Buying local firewood instead of stocking EAB-infested wood can also contribute to rapid tree disease control.

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Beech Bark Disease

Also known as BBD, the disease develops by bark-feeding of scale insects of the genus Cryptococcus. The excessive feeding of these insects causes wounds on the tree bark. Fungi of the genus Neonectria seize the lesions or cankers brought by the insects. When the fungi multiply their spores, the bark slowly strips away, causing tree death. Knowing the signs of BBD can aid in early disease prevention. Scale insects produce a white, waxy substance also made visible by its fleecy texture. Bleeding spots are also noticeable in cankers. Tree disease control comprises of applying lye or paraffin-containing chemicals and by herbicides such as glyphosate.

Dutch Elm Disease

​First identified in the Netherlands and often labeled as DED, this tree illness is caused by ascomycetes or sac fungi that have affected elm trees in both North America and Europe. Bark beetles are accomplices in the spread of destruction as these insects carry ascomycete spores in weakened elm. Sac fungi target the xylem or water vessels of elms, further weakening the tree. The situation finally becomes a gateway for other bark beetles to wreck elms in record time. Disease confirmation is done in laboratories as people can mistake DED for other tree diseases. However, black discoloration of white sapwood can be a helping indicator of DED. Prevention involves targeting beetles primarily by coating bark with methoxychlor or similar pesticides. Disposing of elms both dead and weak is also necessary.

Asian Long-horned Beetle

Credit: D. Gordon E. Robertson Creative Commons

​​Native in both Korea and China, ALB, its shortened name, invades several trees like elm, maple, and ash. This beetle has long antennae and white dots surround its black exoskeleton. A distinct ALB-infected tree symptom is the existence of at least inch-deep "pencil" holes found in the infected tree bark. As the insect bores perforations in the tree, signs of infection include the presence of sawdust on branches. Consequently, the hardwood sap would leech out from the bores, another characteristic symptom. Other than these signs, ALB can also lay its eggs on tree barks, making depressions on tree surfaces. For preventive measures, inspectors set up quarantine areas for slowing the spread. Additional treatments include the application of chemicals and the removal of trees that have high infection potential.

European Gypsy Moth

​Shortened to EGM, the larval stage of these moths are the main harbingers of decimation in various shrubs and conifers. Larvae can cause outbreaks due to their insatiable appetite. This poses threats to North American forests because these organisms cause the increased susceptibility of hardwood to illnesses. The continuity of them feeding on leaves causes loss of foliage in trees. To identify its caterpillar stage, one should find features such as grey & yellow patterns, red & blue dots, and hairy bristles on its body. Cautionary actions involve reporting EGM eggs and larvae to agriculture authorities.

Tar Spot Disease

​This tree disease makes leaves, such as in maple trees, to be covered in spots of yellow and black, resembling tar. Caused by fungi from the genus Rhytisma, the illness is only cosmetic, which means that it only affects leaf surface and is no illness of life-and-death for an infected tree. However, leaf tar spots can enlarge over time, forming clusters. Since this is a disease involving fungal spores blown by the wind, avoiding the occurrence of tar spots in healthy trees needs to start with leaf disposal of affected ones during autumn. Burning, composting, or burying infected leaves is one way to eliminate and limit the presence of the fungi. Copper-containing fungicides for treatment is available but used rarely.

Tar Spot Disease

​These organisms of the genus Neolecanium are scale insects that plague magnolia trees. Brown adults feed on tree sap and discharge honeydew. Their oozy excrement provides growth for fungi that make magnolia leaves and branches look like soot. This circumstance decelerates tree growth and may severely weaken magnolia trees, leading even to death. It is unchallenging to eradicate crawlers or young scale insects, but particularly difficult to target adults because of the critical timing needed for pesticide application. Generally, a tree specialist may want to consider sprays that contain bifenthrin or carbaryl for the eradication of magnolia scale insects.

Tent Caterpillars and Fall Webworms

​It is often confusing to differentiate these pests since both make webs. Tent caterpillars thickly weave their webs on tree forks while fall webworms spurn webs that loosely envelope branches. The former thrives in spring while the latter lives during the summer or fall. Early detection is essential to avoid leaf loss. To prevent further pest proliferation, one should do practices like scouting for egg clusters and removing webs with sticks.

Tree disease control using pesticides is also another option, but it is important to consult first with authorities before deciding to kill pests chemically.

As they say, know thy enemy. One can better comprehend the importance of a tree when faced with enemies such as fungi and insects that threaten their growth. In taking action for tree disease control, we recommend calling an expert like ourselves to assess the disease and offer the correct treatment to ensure the disease does not impact the other trees and plants in your backyard or place of business.