Indoor plants play a vital role in indoor environments, whether it's a home, office, restaurant or other public building. Although they're better protected against weather elements than outdoor plants, they do struggle with insects and diseases. Mites are one of the worst pests that attack indoor plants. Even worse, mites lay eggs on indoor plants. Often these microscopic pests are able to even move through screens or open windows so it's hard to avoid them.
Mites are part of a diverse group of arthropods related to spiders, scorpions and other arachnids, which are a group of anthropods. Plant mites are those mites that feed on plants, while other types of mite are parasites to animals. They have external skeletons (exoskeletons) and jointed legs, but don't have antennae and jaws. They also lack abdominal segmentation.
Spider mites are tiny red bugs that are hard to see without a magnifying glass. These mites suck on a plant leaf and extract its sap, resulting in tiny yellow dots on an infected leaf. This causes infected plants to have a bronze color. Leaves of infected plants then turn brown and fall off. An entire plant can turn yellow and continue to drop leaves as mites multiply, with the plant eventually dying.
Eriophyid mites are transparent and exceptionally tiny, hiding in buds which makes them hard to find. They damage leaf buds, leaving flowers and new leaves discolored. The first sign of infestation is small brown dots on new leaves. Although plants become stunted, they typically don't die.
Usually mites found on indoor plants can be controlled, although it's difficult. Most often it's through nonchemical means. Besides keeping infested plants moderately moist, it helps to apply less fertilizer. Spraying plants with a diluted soapy water solution helps prevent a repeated infestation. The North Carolina State University Extension website recommends applying foliar miticides (pesticides used on leaves that kill mites) at intervals of seven to 10 days.
Spider mites flourish in dry areas, spinning their tiny webs and raising families in dry spaces. Regular plant misting helps eliminate these pests. The Espirit de Isle website recommends misting plants about every two weeks. It's important to spray into the crown of a plant and ensure all new leaves are saturated, including the undersides of leaves.
Misconception and Warnings
It's a common misconception that all indoor plant pests are bad, but phytoseiid mites are actually helpful. Instead of feeding on plants, phytoseiid mites eat spider mites, in addition to other small plant mites.
Although mites usually find their way indoors during warm summer months, they can also come inside a home or building during winter. For example, they can easily come inside a house hiding on greenery and Christmas trees.
Mites can be easily spread on clothing, hands and watering cans. That's why it's important plant caregivers thoroughly wash their hands and tools after handling infested plants.