Fungus on Magnolia Tree Trunk: Identification and Treatment

The lovely magnolia tree is the belle of Southern gardens and is also surprisingly cold-hardy. These sturdy trees are fairly unfussy and low maintenance, but magnolia tree problems can put a damper on the aesthetic and the health of your plants.

Research shows that deciduous species tend to be more vulnerable to pests, while evergreen species are more sensitive to environmental shifts.

Whatever the cause, it is distressing to see one of your trees ailing. Here are 11 common problems with magnolia trees, possible causes, and remedies for returning your tree to good health.

A few different diseases can cause leaves to become discolored, covered in spots, or brown lesions. The most common are:

Phyllosticta leaf spot is caused by the fungus Phyllosticta magnoliae. Symptoms look like small black or purple spots that can gradually progress to larger spots with a halo and white center. This fungus is not a huge problem for mature trees but can be fatal to young trees that aren’t yet established.

Leaf blight is another disease that can cause brown or black spots on the leaves. It generally affects trees that are under stress already. This can happen during drought or when there is a lack of nutrients. Blight is a waterborne bacteria and can cause tip dieback on branches.

The third disease is the most serious and is called Verticillium wilt. This is a fungal infection that affects the water-conducting tissues of the plant. Leaves will turn yellow to brown, and foliage will appear wilted. A soil test is needed to diagnose this magnolia tree problem.

Sadly, there is no fix for Verticillium wilt. Mature trees can outgrow the disease over several years, but the tree’s growth will be permanently stunted. The damage can be mitigated with pruning of affected tissues, proper watering, and fertilizing. Young trees are unlikely to survive. This fungus lives in the soil, so a tree that dies of this should be removed and disposed of. The fungus can live in the soil for up to 5 years.

Both Phyllosticta leaf spot and leaf blight can be helped by quickly pruning away affected foliage. Don’t be conservative about removing any branches you think may be infected. If blight reaches the tree’s trunk, it is fatal. Using hydroxide and copper sulfate sprays are common treatment methods for blight, but pruning is the most effective treatment.

Phyllosticta can be treated with a copper-based fungicide to control the infection. By doing this and careful pruning, this disease should be controllable. It typically does not kill a mature tree. An advanced infection in a younger tree can be fatal.

If you notice leaves beginning to shrivel and curl inward, you probably have an insect infestation. Insects like aphids, scales, and thrips like to feed on the sap of magnolia leaves. As they suck the sap from the leaves, they will begin to curl inward, which can look unsightly but is not typically threatening to the tree’s health.

A mature tree will usually be able to endure insect damage with little overall damage to the plant’s health. However, the tree may suffer if it is young or severely infested.

Generally, no treatment is needed, as insecticides are damaging to beneficial insects as well as pests. Most pests have natural predators that will clean up the problem for you once they find it. If the infestation is severe, treating with insecticidal soaps or neem oil will help control the spread. Treating at night will help to mitigate the damage to pollinators. Try not to treat when the tree is in bloom.

Caterpillars are another common magnolia tree problem. There are several species of moths and butterflies whose larvae like to feed on the leaves. Sometimes this can look like leaves with irregular edges that have clearly been chewed on.

The fruittree leafroller, fall webworm, and cotoneaster webworm are all larvae that feed on magnolia leaves. You may notice that leaves are covered in webbing or have a lacy appearance, as some caterpillars will eat the soft tissue of leaves and leave only the veining intact.

Generally, a mature magnolia will support these insects through their larval stage with no real damage. However, if the infestation is severe enough, these insects can do enough damage to the tree to affect its overall health.

Remove all damaged foliage with clean hand shears. Inspect the trunk and branches for egg masses, and remove and dispose of them by dropping in a bucket of soapy water. Good hygiene practices such as fertilizing, pruning, and watering will keep your tree strong so it can rebound from the damage caused by these insects.

If you notice your magnolia dropping leaves in the fall, you may have a deciduous species. This is a natural occurrence that takes place every year. Your tree is preparing for dormancy, and in the spring, it will grow its leaves back and most likely burst into bloom. Lucky you!

If your magnolia is evergreen, like the popular Southern Magnolia, it will lose some leaves naturally from time to time. If you notice a larger number of leaves dropping simultaneously, you’re most likely to see flowers soon. This is the tree’s way of redirecting resources to flowers and is not a cause for concern.

This magnolia tree problem doesn’t usually warrant a response. Sit back and enjoy the flowers your beautiful magnolia tree is about to produce. On evergreen magnolias, pay attention to where the leaves drop from. If it is preparing to bloom, it will drop its oldest leaves. If more leaves begin to die off and a massive number fall, another issue is probably at play.

Yellow Leaves With Brown Edges

If your lovely magnolia leaves look faded and yellow with dry brown edges, the culprit is probably the weather. It sounds strange to say that sweltering dry weather and very cold weather would cause the same thing to happen, but this is precisely the case.

Very cold, harsh winds have the same effect on leaves that drought has. The leaves appear to be burned because the water evaporates very quickly under these conditions, leading to those dry, brown edges.

The best thing to do is to prune away damaged growth as conservatively as possible and baby the tree for a while. There is not much else to do after the damage is done. You can prevent some of these issues with proper watering during drought, and if the tree is young and small, you can cover it if you know that there will be extremely cold weather.

Magnolia flowers have different lifespans from one species to another. Some varieties, like the giant Southern Magnolia, produce lots of flowers that bloom in succession but only last one to two days each. Others, like M. soulangeana or the Japanese Magnolia, bloom in the spring, and the purple magnolia blooms can last for a week or more.

If you are concerned about flowers turning brown and wilting, the first thing to do is determine how long your specific tree’s blooms last. If the blooms are opening and already have a brown discoloration or look wilted from the beginning, it’s very likely a climate issue. Once again, extreme heat or cold can put stress on a magnolia, affecting the blooms.

There is little to be done about the weather. The best solution here is to keep up with general tree health by watering, fertilizing, and pruning. A magnolia in optimal health will have the least reaction to environmental stress. Make sure to water weekly in times of extreme heat or drought.

If you live in a very cold climate, it’s best to plant your magnolia in a spot that has some shelter from freezing winds. It is the cold winds that typically do the most damage, not the actual temperature shift.

If a magnolia tree is not producing flowers, the issue could be related to sun exposure or soil pH. Magnolias need a fair amount of sun. Most types prefer full sun and will produce the most flowers in this situation.

Soil pH is a little more complicated but can generally be rectified without transplanting. Magnolias like slightly acidic soil. The soil’s acidity helps to break down the nutrients in the soil and fertilizer so that the tree can best utilize them. If the soil pH is too high, meaning too alkaline, the tree will likely become malnourished, and the first thing to suffer will be flower production.

When choosing a spot to plant your magnolia, ensure the area gets at least 6 hours of direct sun daily. If soil pH is the issue, a soil test will give you the necessary answers. Magnolias need a pH of around 6, give or take.

To raise the pH of your soil, add organic material like manure, pine mulch, or compost. Soil acidifiers are also available, but they tend to be more costly. Although they work faster, they do not last as long as amending the soil with organic materials.

Magnolia trees are not fast growers, to begin with. Expect to see 1-2 feet of growth per year, with smaller trees maturing at about 10 years and larger species taking as many as 60 years to reach their full height.

If your magnolia is growing at a snail’s pace, there could be various reasons, from malnourishment to pest infestation. If you’ve ruled out all the other growth-inhibiting magnolia tree problems on this list, nutrition is probably the culprit.

The short answer: fertilizer. But first, make sure your soil pH is right because if the soil is too alkaline, the nutrients in the fertilizer won’t break down in a way that makes them useful to the tree. Check the pH and then make sure you are fertilizing properly.

Magnolias don’t need a ton of fertilizer, but they do like a strategic fertilizing schedule and will flourish when given this. Magnolias should be fertilized 2-3 times during their growing season with a balanced fertilizer.

Spread a granular fertilizer (8-8-8 or 10-10-10 will work great) around the plant’s base in early spring, late spring/early summer, and mid-to-late summer. Fertilizing is particularly important during the tree’s early years.

Leaf and Branch Dieback

This leads us to the dieback of leaves and branches. First, rule out the normal shedding of leaves by a deciduous tree in the fall or an evergreen’s natural shedding in early summer before the flowers bloom. If the leaf drop seems untimely, and entire limbs begin to turn brown and lose leaves, you may have a more serious magnolia tree problem.

The most likely culprit of this in an evergreen magnolia is cold damage. If you had a particularly cold winter, there might be frost damage to some of the outer limbs. Evergreen magnolias are cold tolerant to a certain point, but prolonged periods of extreme cold weather can cause death of the younger growth.

Once the threat of freezing weather passes, prune off dead branches and allow the tree to recover. Giving the tree some fertilizer will help it to produce new, healthy growth, and it should be back to normal by the end of summer.

What is this fungus on my magnolia tree leaves?

FAQ

How to treat fungus on magnolia tree trunk?

Fungicides may be applied if there is evidence of a fungal disease present on your tree. An application of a copper-based fungicide or the Eco product Eric has recommended could be sprayed at leaf fall to kill any fungal spores hiding in the bark or developing buds.

How do you treat fungus on tree bark?

1. Vinegar Spray – You can create a highly effective fungicide by combining one tablespoon of vinegar with one gallon of water. …
2. Baking Soda Spray – make this spray by dissolving 1 teaspoon of baking soda into one quart of water. …
3. Milk Spray – This remedy is one of the simplest!

How to treat powdery mildew on magnolia?

Powdery mildew fungicide: Use sulfur-containing organic fungicides as both preventive and treatment for existing infections. Trim or prune: Remove the affected leaves, stems, buds, fruit or vegetables from the plant and discard.

How can you tell if a magnolia tree is diseased?

Premature shedding of leaves is frequently seen as the tree disease spreads through the magnolia tree’s foliage. If you see dark veining, blossom, and stem tip dieback then contact a tree care specialist immediately! Cankers are wounds and sores that can develop on stems and branches.

Do magnolia trees have fungus?

Just like many other plants and trees, Magnolia trees are usually attacked by various diseases and pest infections. It may also fall victim to fungal issues. The treatment done for fungus depends on the condition it suffers from. Here are the different fungal problems to learn about and how you can treat it: 1. Leaf Spot Diseases

How do you know if a magnolia tree has fungus?

Identification Tips: As the name rightly suggests, the most common symptom is wilting of the leaves and branches. Initially, the leaves turn yellowish with brown margins and develop a scorched look. In magnolias, the sapwood develops a brownish stain, when a tree is infected with this fungus.

Are magnolia trees immune to fungal diseases?

Improve air circulation around the tree by spacing out trees and shrubs or thinning dense foliage to reduce humidity levels. In conclusion, while magnolias are majestic and beautiful, they are not immune to fungal diseases.

What causes black fungus on magnolia trees?

Black fungus on your Magnolia tress is likely one of two things: sooty mold or black mildew. Sooty mold is more severe than black mildew and they require different treatments to remedy. Learn the differences between these two fungi so you can identify the problem with your Magnolia tree.

What causes brown spots on magnolia trees?

Leaf Spot Disease Leaf spot on magnolia trees is a common fungal disease characterized by small, round, brown spots on the foliage. This fungus primarily targets the magnolia leaf during wet conditions. The presence of brown leaf spots, often surrounded by a yellow halo. The spots can merge, creating larger blotchy areas on the leaves.

Do magnolia trees get diseases?

Unfortunately, their beauty can be marred when disease-causing pathogens infect magnolia trees. Sometimes magnolia diseases can be pretty innocuous, while other times they’re fearsome, hard-to-beat afflictions. But no matter the disease you’re fighting, there’s almost always something you can do.