Mites are tiny arachnids that feed on chlorophyll, the substance that gives plants their lovely green color. They are related to ticks and spiders, but feed on trees and shrubs. They are not picky and will infest many species of deciduous and evergreen trees. These pests use their small, sucking mouthparts to extract liquids from plant tissue. Their feeding activity can cause plant foliage to look bleached or bronzed.
Mites reproduce rapidly, often going unnoticed until an infestation becomes severe. As their numbers increase, damage compounds and can impact healthy foliage within a relatively short period. For this reason, early-season management is critical to stop large populations from forming.
Common Types of Mites
There are more than 150 families, though very few are important in terms of damage to trees and shrubs. Some examples include the two-spotted spider mite, southern red mite, the spruce spider mite and the citrus rust mite. Certain types will feed on specific tree species. Conversely, others can be found on many different plants, from vegetables to shrubs to trees, and will spread from one to another feasting on whatever foliage is available.
Signs of Infestation
Though these pests are small, they can be seen on plants and look like little, moving dots. Where feeding occurs and nutrients have been depleted, leaves develop a speckled appearance with pale spots. Another common sign is spider-like webbing on and between leaves, especially when two-spotted spider mite is present.
Keeping Trees and Shrubs Healthy
Infestation is more common, and more concerning, for stressed trees. Examples of stressors include extreme weather like drought or poor soil conditions. Both are problematic for plant health and increase susceptibly to attack. Keeping plants healthy, watered, and mulched is the best protection against infestation. Identifying pests early and responding with treatment to confirmed sightings will keep harmful populations in check. Another effective treatment in some cases is introduction of beneficial predators. For example, you can introduce predatory mites into the environment that feed on spider mites and help effectively manage outbreaks.