Just like humans, and all living creatures, trees get sick and suffer from diseases. However, due to the fact that the trees can not vocally express their stress and illness, their infection or infestation may not be obvious at a quick glance. It takes a keen eye and background knowledge to identify and acknowledge if the tree is sick and what they are suffering from. Questions such as “is my tree sick?” and “how to tell if my tree is infected” often arise with the best interest to protect the tree. To answer questions such as “how to identify a sick tree”, we have amassed a comprehensive list that contains the most common diseases (Infections and infestations) a tree can catch in North America. But just like how you should trust a doctor to diagnose you, you should consult an expert arborist to perform a diagnostic to identify the issue at hand, self diagnosing could lead to a dangerous path of improper treatment. Luckily, we have services for those types of issues.
Becoming more and more common within our maple tree population, tar spots are dark splotches of infection on the leaf of the tree. Despite it being called “tar” spots, the spots do not contain tar, nor do the spots manifest because of the presence of tar. These infections are caused by the pathogen: fungi. The genus of the fungi is Rhytisma, which branches (but are not limited to) to these three common species: Rhytisma acerinum, Rhytisma americanum and Rhytisma punctatum. Despite each species exhibit black spots on the leaves of infected trees, each varying species of Rhytisma has its own distinctive spots. This disease rarely harms the tree, and is rather a question of appearance for the tree. That being said, the disease does not affect healthy human beings, but if you know of someone that has a compromised immune system, it may be your best interest to help prevent infection.
Leaf rust is caused by a fungus pathogen, particularly, from the taxonomy order of Pucciniales (All genus and species of this fungal pathogen essentially all do the same thing to the plant, what differs is the type of plant they infect (Such as trees or bushes) and minor appearance changes within those plant). Leaf rust develops when the Pucciniales fungus develops on the leaf, and if the environment is moist and damp to activate the spores. Pucciniales effectively spreads after sudden moisture or water meets the infected leaf and that touches healthy, non-infected leaves, starting the life cycles of Pucciniales once more. This is also why plant rust happens to spread the quickest after watering the garden or after light rainfall.
Powdery Mildew is a fungus that primarily infects the leaves of a plant. Its genus name is Golovinomyces and the species name oronti (However, it is important to state that there are many different genus and species of powdery mildew that affect different types of plants, and are not limited to oronti). Powdery mildew can be identified as a white powdery substance on the surface on the leaf of a tree or another plant, typically has a texture similar as powdered sugar. This fungus is also the most common infection that you will find on your plants, given that it spreads relatively easily (Through wind and contact with an infected leaf) and proliferates quickly.
Oak wilt is a dangerous disease that can decimates the life of an oak tree. As the name suggests, this disease most commonly infects oak trees, primarily the red oaks. Caused by a fungus pathogen, Ceratocystis (genus) fagacearum (species), oak wilt mostly resides within the northern United States and has not yet been confirmed in Canada. Because a heavy population of oak trees happen to reside within the great lakes, it is becoming more and more a possibility that Canadian oak trees may become infected with Oak wilt, so it is important we keep a keen eye on the condition of our oak trees.
The emerald ash borer (EAB) may be the most infamous invasive species in Ontario Canada. Their impacts on the ash trees are even placed on watch to make sure these insects do not damage more than they do. The genus name, Agrilus and the species name, planipennis, the emerald ash borer are small green beetles that are about 12mm (½ inches) in length and mostly reside around an ash tree. One could say that there is a miniature war going on to protect the ash trees. Here, you will find the basics when it comes to the Agrilus planipennis.
How can I help?
When tending a tree or a plant, it can become difficult if you are relying on online sources to guide you through. You may spend more money that you need for materials and tools that might not even be effective to clearing out the issue. Additionally, you may accidentally do more harm than good if not properly conducted. It is important to let a professional arborist inspect and then act accordingly. That way, you do not accidentally spend money on expensive products and are helping preserve and expand the tree population.