There is a wide variety of magnolia pests. If nothing is done, they can cause considerable damage to your tree.
In this article, we will look at the most common magnolia pests and how to deal with them. I also recommend that you read the excellent article Tips for Growing Healthy Magnolia Trees.
Magnolia pests often include larvae. Omnivorous looper, to be precise. These winged creatures lay eggs from which larvae hatch.
Then the grub begins to gradually destroy the leaf blade. As a result, they eat the soft green part of the leaf, but the veins remain intact.
Usually, the larvae hide in the lower part of the leaf. In addition, they are quite small and not always detectable.
- Inspect magnolia leaves and remove larvae by hand.
- Remove badly damaged leaves.
- Use Trichogramma platneri which parasitizes Omnivorous looper larvae. This wasp is commercially available.
- As a last resort, spray magnolia leaves with a systemic pesticide.
Yellow Poplar Weevil
Yellow Poplar Weevil are fairly large beetles that are easy to spot. They are usually found under the leaves.
This pest makes large holes in the leaves or damages the leaf margin. Large numbers of adults can do a lot of damage to a magnolia tree. This is especially true for young trees.
Yellow Poplar Weevil also lays eggs on leaves. As a result, the larva that hatches begins to feed on the leaves.
- Collect all the bugs from the magnolia leaves and burn them.
- Use beneficial nematodes to kill the larvae.
- Remove badly damaged leaves and leaves with egg clusters.
- Use a systemic pesticide according to label directions.
Aphids are probably the most common pest of plants and magnolia is no exception. These tiny bugs like to parasitize on young leaves and shoots.
Aphids have small, elongated bodies that are gray or greenish in color. Their food is the sap of the tree. They pierce leaf tissue and draw sap from there.
As a result of their activity, the leaf curls up and then turns yellow. If this pest spreads heavily, magnolia trees can lose a significant portion of their foliage.
- Wash the aphids off the leaves with a stream of water from a hose.
- Spray magnolia with a water solution of horticultural oil or neem oil.
- Use insecticidal soap on young and delicate leaves as the neem oil can leave burns.
- Remove dry and badly damaged leaves or shoots.
Scale are some of the most unpleasant pests of magnolia. There is a variety of these insects and some of them are very hard to control.
They have a pretty strong defense in the form of a white covering. Under this covering, they are not afraid of being sprayed with various chemicals.
They can usually be found on the branches and leaves of the magnolia tree. They insert their elongated mouth into the tissues of the tree and feed on the sap from it. As a result of their activity, the lower leaves turn black because of the liquid they secrete.
- If the infestation is minor, remove the pest with your fingers.
- If there are a lot of them, spray the tree with neem oil. This will not kill them but will prevent larvae from hatching.
- In early fall, spray the tree with an insecticide. This will kill any larvae that do hatch.
- Cut and burn branches and leaves that are heavily infested.
Sometimes a pest like a leafminer appears on magnolia leaves. This insect lays its eggs inside the leaf.
After a while, small larvae hatch and begin to eat the leaves from the inside, making tunnels in the leaf blade.
As a result of their activity, chaotic patterns of light green color appear on the leaves. Heavily damaged leaves turn yellow and dry out.
Then the larva transforms into a full-fledged insect and the cycle repeats.
- If 1-2 leaves are infested, tear them off and throw them away from the yard.
- If heavily infested, spray magnolia with horticultural oil and remove all damaged leaves.
- The most effective way to get rid of leafminer is to use a systemic insecticide, but be sure to consult a specialist before doing so.
Borer is not a very common pest of magnolia. But still, it can sometimes infest a tree and it is very dangerous.
Usually, these insects lay their eggs near the trunk of the tree. When the larva hatches, it penetrates the inside of the tree and eats it from the inside.
This pest most often affects branches up to 6 inches in diameter. But in most cases, it will be branches that have just begun to harden.
As a result, all of the leaves above the branch will begin to brown and wither. A large spread of this pest can result in the loss of the magnolia tree.
- If you see the leaves turning brown, inspect the branch from top to bottom for entry holes.
- If entry holes are present, cut off the branch just below.
- Collect all leaves and branches and burn or throw away as far away as possible.
Mealybugs are insects that have rounded and slightly elongated bodies. They are small in size but very visible because they are white in color and leave white deposits around them.
They are able to move on a leaf and reproduce rather quickly. On their backs, they have a fairly strong shell that protects them from many troubles.
The main food of these pests is liquid, which is in the leaves. As a result of their activity, the leaf becomes slightly deformed and may even turn yellow.
- Remove the bugs with your fingers if there are few.
- Use horticultural oil to prevent the eggs from hatching.
- Spray the leaves with insecticidal soap or pesticide.
Thrips are another pest of magnolia. These insects have elongated bodies of small size. They have wings, so they can spread quickly over a wide range.
Females lay their eggs on the ground near the tree. Larvae appear in spring.
These insects parasitize on the leaves of the magnolia tree, feeding on its sap. As a result, the leaves lose their bright green color and may even turn yellow.
- Always keep the surface around the magnolia free of decaying plant debris.
- Purchase and install sticky traps against thrips.
- Or collect or buy ladybugs and spread them on the magnolia.
- Or spray the leaves with an aqueous solution of horticultural oil.