Common Tree Diseases in Ontario
Trees are magnificent living beings, and like all living organisms, trees can become infected with various diseases that can threaten its health, as well as the health of surrounding wildlife. Tree diseases are hard to spot, and many times, homeowners are unaware that their trees are even in distress. With the right information, you can spot the signs of a tree disease or infestation so that your tree can get right back on track.
Below, we will go over some common tree diseases found in Ontario, as well as the signs of disease, and treatment to ensure your tree is healthy and safe:
Below, we will go over some common tree diseases found in Ontario, as well as the signs of disease, and treatment to ensure your tree is healthy and safe:
Emerald Ash Borer
The Emerald Ash Borer (EAB) is an invasive wood-boring beetle native to East Asia. Recognized by its characteristic metallic-green colour, the beetle was believed to have been shipped to North America via wood packaging materials in the early 1990s. Since the introduction of these beetles to the North American landscape, this insect has wreaked havoc, devastating millions of North American Ash trees. Being an invasive species, the beetle is able to ravage North American trees who have little to no resistance to these foreign insects. As a result, an Emerald Ash Borer infestation almost always results in the death of the tree.
The Government of Canada estimates that up to 99% of all ash trees will be killed within 8-10 years once the Emerald Ash Borer arrives in the area. This is why recognizing the signs of an EAB outbreak, and implementing quick intervention tactics, is so important.
The signs of an EAB infestation are difficult to spot, and it will take some very detail-oriented observations to conclude if you have an EAB infection on your hands. Some of the smaller details such as D-shaped exit holes in the bark that measure 1/3 of an inch in diameter, as well as S-shaped galleries or indentations throughout the wood, are good indications of an EAB infestation. On a larger scale, crown dieback, the yellowing and browning of leaves, back deformities characterized by vertical cracks and shoots growing from the lower trunk, and increased woodpecker activity are all indicators that the Emerald Ash Borer has made a home in your Ash tree.
Reporting a possible EAB infestation to the nearest agricultural government institute is the best way that you can help stop the spread of these pests. Eliminating any spare firewood that you have lying around through burning rather than tossing, is also a good way to contain the infestation due to the European Ash Borer’s known habit of infesting firewood and using its transport as a form of transmission.
The Government of Canada estimates that up to 99% of all ash trees will be killed within 8-10 years once the Emerald Ash Borer arrives in the area. This is why recognizing the signs of an EAB outbreak, and implementing quick intervention tactics, is so important.
The signs of an EAB infestation are difficult to spot, and it will take some very detail-oriented observations to conclude if you have an EAB infection on your hands. Some of the smaller details such as D-shaped exit holes in the bark that measure 1/3 of an inch in diameter, as well as S-shaped galleries or indentations throughout the wood, are good indications of an EAB infestation. On a larger scale, crown dieback, the yellowing and browning of leaves, back deformities characterized by vertical cracks and shoots growing from the lower trunk, and increased woodpecker activity are all indicators that the Emerald Ash Borer has made a home in your Ash tree.
Reporting a possible EAB infestation to the nearest agricultural government institute is the best way that you can help stop the spread of these pests. Eliminating any spare firewood that you have lying around through burning rather than tossing, is also a good way to contain the infestation due to the European Ash Borer’s known habit of infesting firewood and using its transport as a form of transmission.
Beech Bark Disease
Beech Bark Disease or BBD is a disease that afflicts American and European Beech trees. Caused by the overeating of bark-feeding scale insects, the resulting cracks and feeding holes left in American and European beech trees offer a pathway for bacteria and fungi to get in and under the bark. Specifically, a particular fungus called Neonectria can enter the tree, allowing the growth and proliferation of fungal spores which can lead to fungal infection and eventually result in death.
The killing fungus, Neonectria, attacks the tree only when there is already extensive damage to the outside bark by the scale insects. Recognizing the signs of beech bark disease and early intervention can actually save the tree if the infestation is found early before the fungus spreads. Common signs of a beech bark disease infestation include deep-red fruiting bodies that jut out from cracks within the tree that appear in late summer and early winter, oozing from the bark, and waxy wooly secretions that cover tree branches. All of these are products of fungal infection and could signal the presence of the bark-feeding scale insects.
Once identified, spraying with an insecticide that specifically targets scale insects is the best approach to manage beech bark disease in its early stages. Treatment in later phases of infestation involves targeting the Neonectria fungus by drenching the lower part of the trunk with phosphites biannually spring and fall is recommended.
The killing fungus, Neonectria, attacks the tree only when there is already extensive damage to the outside bark by the scale insects. Recognizing the signs of beech bark disease and early intervention can actually save the tree if the infestation is found early before the fungus spreads. Common signs of a beech bark disease infestation include deep-red fruiting bodies that jut out from cracks within the tree that appear in late summer and early winter, oozing from the bark, and waxy wooly secretions that cover tree branches. All of these are products of fungal infection and could signal the presence of the bark-feeding scale insects.
Once identified, spraying with an insecticide that specifically targets scale insects is the best approach to manage beech bark disease in its early stages. Treatment in later phases of infestation involves targeting the Neonectria fungus by drenching the lower part of the trunk with phosphites biannually spring and fall is recommended.
Asian Long Horn Beetle
Identified by its long segmented antennae and various white spots on its shiny black exoskeleton, the Asian Long-Horned beetle attacks and kills many different species of hardwood trees, such as elm, ash, and most commonly, maple trees. Originating from Korea and Japan, the Asian Long Horned Beetle was first spotted in Canada in the 1990s when infested wood from plantations was used as packaging material for cargo being shipped to North America. Luckily, Asian Long-Horned beetle populations have been eradicated in Ontario, with only 2 outbreaks occurring in 2003 and 2013 respectively.
Regardless, knowing the signs of an infestation is a good way to make sure that these bug populations stay eradicated. Though you may not see the bug itself, the Asian Long Horned Beetle can leave a lot of tracks that we can use to identify its presence. Some of these signs include the presence of inch deep emergence holes that are about the size of a dime, dripping hardwood sap that leaks out of these emergence homes, and piles of coarse sawdust that the beetles leave from burrowing into the tree.
If you do happen to see the beetle, contact your local agricultural government institution so that they can properly manage the infestation. Unfortunately, no insecticides registered in Canada have proven successful against Asian Long-Horned beetles. The result of an Asian-Long Horned beetle infestation usually involves cutting down the infected tree as well as any nearby vegetation to get rid of any remaining beetles to stop further infestation.
Regardless, knowing the signs of an infestation is a good way to make sure that these bug populations stay eradicated. Though you may not see the bug itself, the Asian Long Horned Beetle can leave a lot of tracks that we can use to identify its presence. Some of these signs include the presence of inch deep emergence holes that are about the size of a dime, dripping hardwood sap that leaks out of these emergence homes, and piles of coarse sawdust that the beetles leave from burrowing into the tree.
If you do happen to see the beetle, contact your local agricultural government institution so that they can properly manage the infestation. Unfortunately, no insecticides registered in Canada have proven successful against Asian Long-Horned beetles. The result of an Asian-Long Horned beetle infestation usually involves cutting down the infected tree as well as any nearby vegetation to get rid of any remaining beetles to stop further infestation.
Dutch Elm Disease
Spread by elm bark beetles, Dutch Elm disease (DED) is a disease that causes widespread damage to elm and similar trees. This disease is caused by sac fungi called Ascomycetes that is present on burrowing bark beetles. When female bark beetles target weakened elm wood to lay their eggs, this fungus on the beetle can enter into the egg-laying galleries and multiply. When the young adult beetles hatch and emerge from the bark, they carry the fungal spores on their bodies, which can go on to infect even more trees.
DED is difficult to diagnose since its symptoms are so similar to other tree diseases. Testing in a lab is usually required for confirmation, but the average person can still identify the signs of DED infection on their elm trees. Some indications of the disease include yellowing and wilting leaves on individual branches, as well as brown streaking along the sapwood of wilted branches when the outer layer of bark is removed.
DED infections can be managed if caught early. Any and all dead or dying elm wood should be burned or buried before the elm tree leaf out in early spring. Spraying the tree with an annual insecticide will effectively kill the beetles that carry the fungus, while an injection of fungicide into the sapwood will eliminate the fungal spores themselves.
DED is difficult to diagnose since its symptoms are so similar to other tree diseases. Testing in a lab is usually required for confirmation, but the average person can still identify the signs of DED infection on their elm trees. Some indications of the disease include yellowing and wilting leaves on individual branches, as well as brown streaking along the sapwood of wilted branches when the outer layer of bark is removed.
DED infections can be managed if caught early. Any and all dead or dying elm wood should be burned or buried before the elm tree leaf out in early spring. Spraying the tree with an annual insecticide will effectively kill the beetles that carry the fungus, while an injection of fungicide into the sapwood will eliminate the fungal spores themselves.
European Gypsy Moth
Gypsy moths are a persistent pest that show up every couple of years and bring with them a string of chaos. Native to Europe, these moths multiply in very large numbers and can be a constant nuisance in the warm, summer months. What may be a small nuisance for us actually poses a very large threat to trees. European Gypsy moth larvae have enormous appetites. Their diverse and indiscriminate palette includes more than 300 species of trees and shrubs, and it is their excessive feeding patterns while in their larval stages that causes major loss of foliage in trees. This exposure can leave trees vulnerable to diseases and other pests, and poses a serious threat to North American forest survival as well as the animals that depend on these trees for their habitat.
The signs of a European Gypsy Moth infestation are easy to spot. You may spot the culprits themselves - caterpillars with grey and yellow patterns, red and blue dots, and hairy bristles all along its body, or fuzzy tan-coloured egg masses that are stuck to tree trunks or outdoor furniture. Some subtle signs include holes in leaves from the caterpillar’s feeding, and excessive damage to the foliage of trees.
These pests can be a nuisance, but luckily, they can be dealt with quite easily. You are most likely to see these caterpillars arise in May and June. Collecting them off plants and praying with an approved pesticide is sufficient to eliminate them. To trap and collect caterpillars for easy extermination, wrap the affected trees with wide bands of burlap. Gypsy Moth caterpillars love burrowing in the burlap, which will allow for quick and easy collection of many at a time. Getting rid of egg masses that are seen on the surface of trees or furniture soaking them in soapy water will help to prevent infestation next year.
The signs of a European Gypsy Moth infestation are easy to spot. You may spot the culprits themselves - caterpillars with grey and yellow patterns, red and blue dots, and hairy bristles all along its body, or fuzzy tan-coloured egg masses that are stuck to tree trunks or outdoor furniture. Some subtle signs include holes in leaves from the caterpillar’s feeding, and excessive damage to the foliage of trees.
These pests can be a nuisance, but luckily, they can be dealt with quite easily. You are most likely to see these caterpillars arise in May and June. Collecting them off plants and praying with an approved pesticide is sufficient to eliminate them. To trap and collect caterpillars for easy extermination, wrap the affected trees with wide bands of burlap. Gypsy Moth caterpillars love burrowing in the burlap, which will allow for quick and easy collection of many at a time. Getting rid of egg masses that are seen on the surface of trees or furniture soaking them in soapy water will help to prevent infestation next year.
Tree Assessment in Durham Region
Knowing the right signs of tree infections can help you to identify if your tree is under the weather and enable you to get better and faster help when it matters. We have seen tree diseases of all kinds, and through early diagnosis and quick action from skilled professionals, many trees can fortunately be saved. We are your tree doctor of choice with expert arborist to perform a proper tree assessment and diagnosis followed by a prescribed treatment if it will benefit the tree and save it from a complete tree removal to protect your other trees. We service all of Durham region and have tress assessment services in Pickering, Ajax, Whitby, Oshawa and Uxbridge.
