Spider mites are one of the more challenging houseplant pests. To successfully defeat them, you need to attack repeatedly.
Spider mites are, unfortunately, one of the more common houseplant pests. Unfortunately, they're also one the more difficult pests to get rid of.
Identifying Spider Mites
The telltale sign your plant has become infested with mites is their webbing. These critters produce fine webs that look like cobwebs. They usually start out on the undersides of the leaves. As the infestation grows, you may see them on the tops of the leaves, as well as on plant stems.
Spider mites create a stippled look --- like the leaves have been pricked with tiny needles --- as they feed. As populations grow, they take more and more energy from the leaves. This causes the foliage to go brown and dry premature.
Fighting Spider Mites
The earlier you start to treat spider mites, the more effective it will be. These pests have a fast reproduction rate. An adult can lay eggs that hatch, grow, and develop into an adult that can lay more eggs in a week.
Start with Growing Conditions: Spider mites love warm, dry air. They spread fastest in these conditions. (Which is why they're often more of a problem in winter.) The cooler it is, and the more humid it is, the slower they will spread (and the easier it will be to stop them).
Wash Your Plants: Regularly rinse off your plants (especially the bottoms of the leaves) with room-temperature water. This dislodges some of the spider mites and creates the type of wet conditions they hate. Weekly washing can be helpful.
Spray Your Plants: The next step to take is spraying your plants. Using an oil, such as neem, can be effective. Because spider mites reproduce and start new generations quickly, the key to spraying is to do it regularly. Once a week to 10 days for a month or so (or as recommended on the the product packaging) may be necessary.
Note: There are both organic and synthetic formulations of neem oil available.
Use Beneficial Insects: If you don't mind good bugs around your home, invest in beneficial insects that feed on spider mites. This strategy is best for light infestations or after you've sprayed. Beneficials naturally attack populations for you. Predatory mites, for example, consume harmful spider mites. (These tiny predatory mites don't feed on plants, and don't bother people or pests.) Ladybug and lacewing larvae also feed on harmful spider mites.