White spots on magnolia leaves are problems that would keep you worried, but you shouldn’t be afraid about your magnolia dying. Although some white spot contents may hide some potentially serious issues.
Taking a closer look at your magnolia tree will help you understand what’s going on with your tree so that you can reach a better solution decision. Without further ado, let’s get into it.
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What Are the Causes of Magnolia White Spots?
The causes of magnolia white spots are powdery mildew and algae leaf spots. In addition to these, they would also be due to magnolia scale that could attack it, and scoot mold that would develop and weaken your beautiful tree.
– Powdery Mildew
This is probably the number one because you should think about when it comes to white leaves on any plant. You should note that this fungal disease isn’t season-related and can creep up on you at any given point, but it usually loves humid and hot weather.
In addition, remember that powdery mildew can be present long before it starts to show itself. This means that you will see its impact, but just as it has developed well, that is when it is going to be more obvious.
Spots are formed by thousands of microscopic spores all clumped together on your leaves. These fungal cells are dispersed by wind and find their way onto leaves either via water or rain droplets or entering through the soil and roots. Pretty much unavoidable, this one, but don’t worry, as it is not deadly by any means.
Identifying powdery mildew is fairly easy too; what you could do is simply run your fingers through the spots, and if it smudges and follows your finger, then, you have a case of powdery mildew on your hands. This disease will likely show itself on top of the canopy first, finding its way down as it progresses. Also, make sure that you do not spread it over other plants because they could b contagious.
– Algal Leaf Spot
Algal spots can be caused by one of four common fungi species; hence, they leave white spreading dots. Actual spots are almost always white in the center and black, red, and brown on the edges. These spots don’t just attack magnolias, and if you do spot them you should check your other ornamentals.
These spot-causing fungi thrive in moist conditions and all it takes is a drop of water to make these germinate and spread like wildfire on the leaf because they would increase when the medium is humid. As soon as the fungi interact with the water and penetrate the leaf, your plant is diseased.
Leaf spot is likely to spread and germinate in periods of high humidity and should clear out on their own as soon as it gets dry and sunny. In humid climates, the algal spot is a natural seasonal occurrence on mature trees.
– Magnolia Scale
If your spots look more like bumps, then you may just be dealing with a scale. This is a common sap-sucking pest that can potentially be dangerous to trees and even cause them to die. They look like little cotton-like dots arrange next to each other, and when they develop, they would be all over the leaves and the stems.
These small insects tend to cluster and mush together on tree branches, sucking the sap from the tree. Much like aphids and any other insects, these will release honeydew, a sap-like substance that will surely indicate that there’s a presence of insects. If you aren’t sure whether or not you have these insects, you may want to call a professional, to indicate the matter.
In this case, you would worry, because, in general, magnolia trees love full sun to partial shade, growing well in moist, slightly acidic, rich, and well-drained soils, so if these scales hit the plant, you would worry as they start to change the beauty of the plant. The matter would take over if the conditions aren’t met any longer than what they are supposed to be.
– Sooty Mold
Another non-harmful magnolia condition is a sooty mold. This is a frequent disease, first looking like white powder, then turning black and rather unsightly. It can occur at any point on the tree, but usually follows an infection of sap-sucking insects like aphids, and they would show on the center vein of the leaf.
These insects secrete honeydew, which is a sap-like substance that falls on the leaves and provides an environment for the saprophytic fungi to breed. Fortunately for you, this disease doesn’t attack plant tissue and is just a direct result of resin or sap drying up on your leaves. If you have a presence of soot-like mold, then your problems are likely caused by aphids, which you should look for above the leaves covered in soot.
What Are Ways of Dealing With White Spots On Magnolias?
The ways to deal with the white spots on magnolias are to apply some fungicidal liquid on them, prune and treat the rest of the plant. In addition, you should also spray some insecticides on the leaves, or spray alcohol and water solution.
– Apply Some Fungicidal
If you notice powdery mildew on those leaves and petals of yours, you may be alarmed. However, powdery mildew is absolutely a normal condition with magnolia trees. Nevertheless, if you want to get rid of it is a possible way to reverse the health of your plant back again.
Start by cutting and removing any infected leaves you spot, because magnolias and other trees will recover great from seasonal pruning, and even if mildew wasn’t harmful, to begin with, the tree might benefit from partial defoliation.
After the leaves have been removed, you can soak the tree with a mixture of water and rubbing alcohol or regular soap, what this does is that it will disinfect all the remaining areas and make your tree clean.
If you’re not a big fan of fungal diseases, you can always reach for some prevention methods. A general fungicide applied two to three times a year will do the trick and help your magnolia ward off fungi.
– Pruning and Treating
If you spot leaves with five or more spots on them, you’re free to tear them off and throw them away, you should do this matter by properly pruning the infected leaves. After this, a copper-based fungicide should be applied to your magnolia tree every seven days until you see signs of improvement.
The reason why you should do this is that you are going to protect the plant from any harm that possibly comes.
In this case, you should avoid getting the environment overly moist to prevent further fungi germination, and they would develop once more. To prevent the algal spots from even happening you should fertilize and water the magnolia properly and avoid irrigation systems that will spray the water onto leaves.
– Apply Some Insecticides
Scale and aphids are a bugging issue that can lead to all sorts of problems and further disease spread. Insects are best dealt with by the use of insecticides, but you don’t want to use overly aggressive substances for these microscopic beings. There’s a perfect homemade solution that works every time if you do not wish to apply any chemical-based solutions.
You can also try to buy some neem or horticultural oils, and apply them to the plant. Highly effective at making pests unstuck from the leaves and choking their small suckers.
In this case, just mix a good spoon or two of neem oil with a gallon of water and spray the entire tree and let it dry. After this, you can go through the tree and remove the remaining insects with some rubbing alcohol and water solution.
Baking soda is another highly effective ingredient you can use, either with oils or alone. Now, make sure you’ve done a good job by going through the tree with the rubbing alcohol or hand soap solution. If some leaves have curled up or gone yellow due to the scale, you can freely cut them off and throw them away, with a sterilized pruning blade.
– Spray Some Alcohol and Water
This disease isn’t a tree disease, but rather a disease of resin fallen on the leaf, and with this in mind, there’s nothing much you should do to treat soot mold. But you don’t have to remove the leaves; on the contrary, simply mix some rubbing alcohol and water and gently rub the mixture on the leaves, until you’ve cleaned the soot away. If it’s too hardened, you can cut some infected leaves.
Magnolias are the true beauties of the garden, and unique specimens every gardener is proud of. These beautiful trees also have astonishingly beautiful leaves that can, unfortunately, get white and there’s more than one cause of it, so let’s check what we covered here:
- Always make sure you’ve taken a step back and inspected your magnolias thoroughly. Even cutting back on the water for a few days won’t hurt them and will surely prevent fungi from spreading.
- Your number one most likely culprit is powdery mildew. Gently run your fingers through the white stain and if it leaves a smudge, then you’re dealing with it.
- Other potential whitening issues can include soot mold, which will point to the breeding season and activity of aphids and scale too.
- Fungal diseases can get your magnolias in a weakened state, so make sure to apply fungicides at least two times in the growing season.
Magnolias are wonderful garden beauties, perfectly accentuating any spot they find themselves in. These flowering trees are prized for their incredible flowers and adorable spring fragrance, and now that spots aren’t an issue anymore, we’re sure your magnolias will grow strong and healthy for years to come.