Tree Service: Disease Identification, Prevention, and Treatments

May 16, 2018 Tree Care



Spring is here, and it’s time to plan out your garden, plant new flowers, prepare the lawn, and check out how the trees and shrubs made out this winter. The best way to keep your outdoor living space in top shape is to manage the identification, prevention, and treatments for backyard plant life. If a tomato plant becomes diseased, it is easy to pull it up and throw it away. If a tree or shrub becomes diseased, it can be a more difficult process. Trees with disease can range from an aesthetic deformity, all the way to the complete death of the tree.

To avoid having to take a tree down, learn about these common tree and shrub diseases and how to manage them!  The critical step is identification of a problem, once your plants have been checked, consulting with a tree care company for treatment and ongoing oversight of your trees and shrubs preserves the investment you have made in your property.


1. Anthracnose


This is a leaf disease specific to the eastern United States. It comes from the fungi in the genus Colletotrichum and can be seen from the browning and deterioration of leaves. In the beginning stages, cool and wet weather promotes the development of the disease. Anthracnose disease is then exacerbated by hot and humid conditions and the lesions it creates in plantlife often become covered with pink, gelatinous masses of spores.

To treat this and prevent it from spreading, be sure to completely remove and dispose of all infected plant life off the property. Don’t throw it off to the woods as it will come back next season. Clean all gardening utensils with one part bleach to four parts warm water. Purchase a fungicide and spray the infected areas or hire your certified Plant Healthcare professional to apply a fungicide. After the initial fungicide treatment, copper sprays and sulfur powders should be applied to the infected areas weekly. 

In the case of trees specifically, Anthracnose deteriorates the health and look of a tree, but it is unlikely to cause permanent damage. The real problem with Anthracnose Disease within a tree is that it weakens the tree, leaving it vulnerable to hurtful pests that may actually kill the tree. Hire a tree care company to provide a tree service that could save the tree.


2. Stem Cankering and Shoot Blights



Photo: Cankering of an Apple Tree

While there are many causes and types of cankering and blights, there are some more common in the New Hampshire Lakes Region region. Stem cankering and shoot blights happen when fungi/bacteria infect the flowers and leaves of a tree, which moves down the shoot and causes cankers. This bacteria overwinters in fruit or dead leaves. To identify, you will see browning and limpness in the foliage of the tree. Aside from the health of the tree, these diseases can be especially frustrating with trees that produce fruit. Apple trees are often the victim of stem cankering and shoot blights as it is carried by fruit. This causes bruising and molding of the fruit.


While there aren’t many treatments for a cankering tree, there are preventative measures that can be taken. Only grow trees that are domestic and be sure to conduct proper maintenance like watering, pruning, mulching, and soil management. If your tree is starting to grow growths over the cankers, do not cut them off as it is part of the healing process.


3. Ploioderma Needle Cast


The fungus Ploioderma lethale causes Ploioderma Needle Cast on two- and three-needle pines. Once a tree is infected, it takes six to eight months to show symptoms. This includes browning and blighting of the needle pine tips and black strips of fungus tissue on the epidermis of blighted needle sections. These black strips eventually grow into orbs that burst and spread clear spores all over the tree. The disease is then carried on to other trees from wind and rain.

Ploioderma Needle Cast can easily damage and kill a tree, which is why it’s so important to treat the fungus as soon as it is spotted. The most damage usually happens at the lower branches where there is less air flow and more humidity. Infected shoots should be pruned and removed from the site. Trees that are easily predisposed to drought or insect feeding should be treated with a fungicide combination of copper hydroxide and mancozeb by a licensed professional.


4. Vascular Wilts


Vascular wilt is caused by fungi that enter the water-conducting xylem vessels and constrict the plant’s ability to push water through its vessels to all parts of the tree.The first sign of vascular wilting is leaves curling and then later wilting and discoloring.  The wilting eventually results in the death of the outermost parts of the tree, then it spreads to the limbs, and lastly to the trunk. This makes vascular wilting one of the most devastating plant diseases.

Treatment for vascular wilts can be difficult because by the time you’ve spotted the disease it has already spread to the xylem vessels. For small and less expensive plants, it is recommended to just dispose of the plant. For larger plants like trees and shrubs, extensive care should be given to help the tree keep its immune system up. It is recommended to seek the help of a certified Plant Healthcare to try and save the tree. Specific treatment would This includes using a low nitrogen and high phosphorus fertilizer, consistent watering, pruning, and soil solarization. The process of soil solarization is more complex, and may require the help of a professional arborist.


5. Root and Butt Rot


The most common reason for a tree rotting is from moist conditions that make the tree an excellent host for fungus and bacteria. The most difficult to treat is root and butt rot, which occurs at the base of the tree. If fungus is growing on the limbs, you can cut the limb off. However, if fungus is growing at the base, there is no way to completely eradicate it without doing severe damage to the tree. This fungus,  similar to vascular wilts, damages the xylem tissue. Root and butt rot also leaves the tree vulnerable to toppling over.

There is no treatment for root and butt rot, but there are ways to prevent rotting. When planting trees, be sure to plant them in a place that isn’t a good host for bacteria and fungus. For example, a moist and dark area of the property may not be the best spot to plant a tree. Also, the stump of a tree that was cut down due to root rot should be removed entirely so it doesn’t infect other trees.


6. Foliar Powdery Mildews



Powdery mildew is a foliar disease that produces a white, powder looking fungus on the tops of leaves. It is more common in the summer and early fall, and is much less serious than other diseases on this list. If it is not treated, however, it can cause leaves to become distorted, buds can become stunted, and fruit may fall prematurely from the tree. Birch trees are more susceptible to this issue, so preventative measures should be taken to avoid future damage.

If you see powdery mildew on your tree, you can remove the diseased leaves as they drop and take them off the property to avoid spreading the disease. This is considered one of the less serious tree problems to have as it doesn’t threaten the life of the tree, but some people may find it unsightly.

Tree diseases vary in severity and treatment plans, but the thing they all have in common is that they can be prevented. By taking steps to prevent these diseases, it is much less likely you will encounter these problems in the first place. Hiring a professional tree care team that is knowledgeable about these preventative measures and licensed to apply treatments makes a significant difference in the health of your trees and landscape. If you have a tree or shrub that needs removal, don't wait to call your landscape professional for tree removing services. 

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