Spider mites are the most common mites on houseplants. Of the more than 20,000 known mite species, about 1,200 of them are some type of spider mite. An arachnid, most mites have two body segments and eight legs. Some mites, like chiggers, only have six legs. These are not nice bugs. Because they love to eat plants and breed, spider mites on houseplants can quickly decimate your growth, starting with the relatively innocent symptom of yellowing leaves, and eventually destroy the plant. Learn what to do about these houseplant pests.
Types of Houseplant Mites
The two-spotted spider mite (or red spider mite) is by far the most common species of houseplant mites. One of the big reasons the two-spotted spider mite has become so common is that it’s well adapted to feed on hundreds of different types of plants, including many houseplants. Although it’s sometimes called the red spider mite, it can also be green, orange-brown, or translucent. An infestation may produce green spider mites at first but red spider mites in later generations as the infestation spreads. Because spider mites like dry, hot conditions, houseplants that have been underwatered are especially vulnerable to this pest.
That said, there are thousands of types of houseplant mites. Broad mites and cyclamen mites are two relatively common species within the tarsonemid mite family. Eriophyids are another large family of mites. These species are often known by common names that describe the type of damage they inflict: blister mites, rust mites, bud mites, and gall mites. Other mite species like specific types of plants. The spruce mite is found almost exclusively in spruce trees, for example.
How to Identify Spider Mites on Houseplants
Even in their adult stage, most spider mites are only about one-half millimeter big, making them hard to find and identify them directly until the infestation is widespread. There are generally two ways of first noticing spider mites. These mites create webbing on plants to protect themselves from predators. The other way is damage to the plant. Spider mites will burrow into plant leaves and suck out the sap. This usually causes the leaf to yellow at first before dying back altogether. By this time, the mites have likely spread to other parts of the plant. If you’re not sure what’s causing damage to your plant, take a tissue and run it along the underside of the affected leaves and surrounding growth. If the tissue is spotty with blood, you probably have mites. With advanced infestations, you can knock the mites off of leaves onto white paper and examine them under a magnifying glass to identify the exact species.
Spider Mite Pest Control and Treatment
The first step is to remove as many of the mites as you can by spraying the plant vigorously with water or a specially formulated product in a safe space away from other houseplants. There are miticide products available that are great for targeting spider mites, but which may not be effective against all kinds of mites. There is also a family of predatory mites (phytoseiidae) that is especially adept at preying on spider mites.
A general insecticide soap or oil may not be as instantly lethal but will control most types of mite species. Likewise, ladybugs are great at feeding on spider mites, as well as most every houseplant pest. If you’re not sure exactly what type of mite is attacking your plant, it’s prudent to start with a general insecticide. But don’t wait to start treatment. Depending on the temperature and environmental conditions, it takes about 7-14 days for a spider mite to go from egg to larva to nymph to adult mite. An adult female may lay about 100 eggs during its three-week lifespan.
How to Prevent Spider Mites on Houseplants
The best spider mite prevention starts with good houseplant care and strong, healthy plants. Spider mites like dry conditions; they also like dust. Regular misting or cleaning the leaves is a good preventative step for houseplant care. This doesn’t mean you should overwater plants that are susceptible to root rot. Inspect new and outdoor plants as closely as possible before introducing them to an area with other houseplants. Finally, if a houseplant has suffered from mites in the past, it’s a good idea to apply a general insecticide or introduce ladybugs to protect against future infestations.
Cost-Benefit Analysis of Treating Houseplants for Spider Mites
When caught early on, it’s definitely worth treating houseplants for spider mites. The problem is that many infestations are only identified in advanced stages. It’s all too easy to misdiagnose early warning signs as some other trouble the plant is having. Widespread mites are difficult to get rid of completely. Often, the best plan is to discard or remove the plant and take steps to prevent the mites from getting a foothold in other houseplants. Not sure if you’re dealing with mites or some other pest? Check our general guide to identifying and controlling types of houseplant pests.