If an apple tree is dying, it is because an environmental factor is causing it stress and affecting its overall health. If you think there is something wrong with your apple tree, you need to act quickly to diagnose the ailment in order to correctly fix the problem.
The most common causes of a dying apple tree are Nectria canker, woolly aphids, fire blight, Frogeye leaf spot and Phytophthora rot.
In this article, we will discuss the various reasons your apple tree may be dying, and how to save it.
Why is my apple tree dying?
This fungal disease is caused by the Nectria galligena fungus. It attacks the vulnerable wounds on the tree’s branches, causing sunken areas. When the branches get severely infected, they will die back and fall off.
Several factors make the apple tree susceptible to Nectria canker, including root damage, bad pruning techniques, diseases, pests and injuries. If your tree is healthy, you do not have to worry about this disease because the tree will be more than capable of staving off the infection on its own. Only newly transplanted trees, young or old trees and unhealthy trees have a high risk of infection, and most of these actually die from it.
You can tell a tree has nectria canker when there are discolored, sunken and dead areas on the trunk and branches. The leaves will wilt and the fruit will rot.
Treat nectria canker by pruning off any infected twigs and branches. If you have to remove a big branch, do so and paint over the stump immediately with wound paint.
These are a type of aphid that feeds on the sap of the apple tree. First, they will attack the bark and the stems, but they can progress to the roots if the infestation is not dealt with. These insects may be minute and unassuming, but if there are enough of them they can really do some damage to the tree, making it vulnerable to even more opportunistic pathogens.
You can tell that your apple tree has woolly aphids if you see that the bark of the tree is being attacked, but the leaves are largely unaffected. You will see a white, fluffy substance on the bark, and if you scrape it off, you will find brown bugs feeding on the sap.
You can get rid of the aphids by using neem oil on the affected areas. This is useful in small-scale infestations. If the infestation is large, you are better off using pesticides. If there are any severely damaged branches, prune them off. Repeat the treatment if necessary, until you have killed every single aphid.
This disease is caused by the Erwinia amylovora bacterium, a lethal disease that is highly contagious. The infected tree will pass the bacteria to the twigs and the blossoms, from where it will be spread to other trees by birds, rain, wind and irrigation water.
You can tell that an apple tree has fire blight if its blossoms look scorched and brown. The branches will then become affected, the leaves will wilt and the twigs will curl. The branches will have cankers with orange-colored liquid, making the tree look like it is on fire – hence the name of the disease.
You can save an apple tree with fire blight by pruning off any dead or infected branches during the late winter when the tree is dormant. Make sure you do not prune during the growing season, because this only causes the disease to spread even further. Burn all branches that have orange ooze. If the fire blight was severe the year before, make sure you spray fungicide on the tree before it blooms.
Frogeye leaf spot
This disease is also called black rot, and is another deadly apple tree disease. This is a fungal disease caused by Botryosphaeria obtusa, and can affect the branches, trunk, leaves and fruit of the apple tree.
Specifically, the frogeye leaf spot refers to the stage of black rot when the leaves are infected. Once the fungus reaches the fruit, it is referred to as black rot. This disease is definitely capable of killing the tree, especially once it reaches the branches.
Symptoms of frogeye leaf spot or black rot are purple spots on the leaves; these spots will enlarge into brown circles with a purple margin. The spots look like frog eyes. Near the end of the blossom, rotten spots will develop on the fruit and the fruit will dry out while still on the branches.
You can save an apple tree with frogeye leaf spot by using proper sanitation. Prune off all the infected branches and fruit, and dispose of them properly. Prune any area showing signs of leaf spot as soon as possible.
Trees that are already infected with fire blight will be more susceptible to black rot. To avoid black rot, avoid fire blight first. As mentioned above, prune the tree in the dormant season as opposed to the growing season, so the fire blight does not spread.
This is the most common cause of root rot in apple trees. It is caused by a fungus that affects the base and the root of the tree. It is also called root rot, crown rot and collar rot.
The differences in the name depend on the location of the infection: Collar rot happens in severe infections and is visible above the tree union. Crown rot affects the crown system of the roots and the trunk base. Root rot, meanwhile, refers to the infection that occurs in the roots.
Symptoms of Phytophthora rot mostly go unnoticed in the early stages and only become noticeable when the disease has advanced into the tree. As the disease progresses, the branches will start dying and the leaves will turn yellow, wilt and fall off the tree. These above-ground symptoms are not unique to Phytophthora rot, so you may need to examine the roots themselves to be sure. The root system will appear weakened, there will be rotten feeder roots, and the larger roots will be rotten and decayed.
You can test to confirm a Phytophthora infection by cutting off a piece of root bark with a knife. If the inside of the root is green, it is healthy, while an infected root will be brown or orange.
You can save a dying tree by removing the soil around its base and exposing the affected areas. When you leave the roots exposed, they will dry out and temporarily stop the spread of the disease. Spray the roots with fungicide and place new soil over them once they are dry.
If your apple tree is dying, it is most likely due to pests or disease. These pathogens cause stress to the tree, which affects its overall health. Make sure you address the problem as soon as possible so that damage is minimized.
The most common causes of a dying apple tree are Nectria canker, woolly aphids, fire blight, Frogeye leaf spot and Phytophthora rot. Do not ignore any of these infections, because they are all capable of killing your beloved apple tree.
Image: istockphoto.com / Tarja Jalkanen