The flowering almond, also known as Prunus triloba var. multiplex, has a moderate growth rate---reaching a height and spread of 12 feet. It is not native to North America and is hardy in zones 3B through 6B. In mid-spring this lovely specimen and ornamental tree is filled with gorgeous double pink blossoms. Aphids, borers, scales, spider mites and tent caterpillars are pests that could possibly attack the flowering almond.
The symptoms of an infestation of aphids on a flowering almond tree will be: new growth/leaf distortion, honeydew deposits and sooty mold. Aphids suck the sap from plants, causing the leaves to curl up, wilt or die. Their waste material is known as "honeydew," and if a large number of aphids have infested the tree, the honeydew will be a problem---as it will cover the sidewalk, leaves and branches. Sooty mold can then form or grow on the waste material. Control aphids with insecticides or by their natural enemies, including lady beetles, flower fly larvae, lacewing larvae and parasitic wasps.
Flowering almond trees under stress or unhealthy are likely candidates for an infestation of borers. Symptoms that your tree may have borers are: sawdust-like excrement near one of their exit holes in the tree or on the ground, and sap at the wound in the tree. The holes that borers make in the tree can be round, oval or D-shaped. Borers can kill a part of the tree (branch), or they can kill the entire tree. One basic way to avoid having a problem with borers is to keep your tree stress free and healthy by watering, and maintaining a regular fertilization program. Another choice is to have a professional apply an insecticide as a preventative measure.
Scales are yet another pest that sucks the juices of the tree, and they are quite common. If your tree has a heavy infestation of scales you will see small, round growths on the tree. The insect is underneath the growth and is feeding or sucking on the juices of the almond tree. Two types of scales exist they are: armored scales and soft scales. A severe infestation of armored scales will kill a tree. Symptoms of armored scale infestation are: the leaves will turn yellow and fall from the tree, some of the twigs and limbs may die and there is a possibility that the bark can crack and gum.
Soft scales on the other hand will not kill the tree---they will cause the tree to become less vigorous. But soft scales do produce a lot of honeydew (waste material) that can lead to sooty mold. Natural enemies of both armored and soft scales are ladybird beetles and small parasitic wasps. Insecticides can also be applied to control an infestation of either type of scales. However, most important is to keep your trees healthy through watering and fertilization, as scales attack a stressed or weak tree.
Spider mites are arachnids that also attack the flowering almond tree by sucking or feeding on the leaves. Symptoms of the infestation are yellowing and dropping of leaves. A severe infestation will produce webbing on the leaves and branches. Due to their minute size, spider mites will be very hard to detect until the symptoms are apparent. Their natural enemies are: ladybugs, lacewing larvae, minute pirate bugs and some predatory mites. Spider mites attack a stressed or weakened tree; therefore, it is imperative to maintain the health of your flowering almond tree through watering and fertilization. The undersides of leaves can also be sprayed with water to dislodge the spider mites from the tree.
Tent caterpillars eat the leaves of the tree, moving from branch to branch. They can defoliate an entire tree. A healthy tree will be able to grow new leaves. You can control tent caterpillars by removing their egg cases from the tree. The egg cases are found on twigs, they are brown or gray in color. These hard 1½-inch long egg cases should be pruned away or taken off by hand. If the tent caterpillars have hatched then you should remove and destroy their nests, by pruning or taking them off by hand. You can also spray the tree with an insecticide, such as Bacillus thuringiensis (Bt).