Spider mites are tiny arachnids that belong to the family Tetranychidae. They are often found on the undersides of leaves and can be difficult to see without a magnifying glass. These pests feed on plant sap, which can lead to yellowing leaves and stunted growth. There are many species of spider mites, with the two-spotted spider mite being one of the most common. They thrive in warm, dry conditions and can reproduce rapidly, making them a significant threat to crops and houseplants. Effective management includes maintaining humidity and using insecticidal soaps or miticides.