Red spider mites are not insects, but are instead closely related to spiders. They are commonly seen on both houseplants and outdoor plants, and an infestation can eventually kill plants. Because of their small size and prolific breeding, they can be difficult to get rid of.
Barely visible to the naked eye, adult red spider mites are approximately 1/50 of an inch (0.4 mm) in length. Like spiders, they have no antennae and four pairs of legs, and are capable of spinning silk webs. Females are larger than males.
Instead of directly consuming the leaves or stems of plants as most other insects do, red spider mites have specialized mouth parts that pierce the plant cells and allow them to feed on the contents of the cells. This causes tiny yellow or brown spots to appear on the plant, signs of a feeding practice that will eventually cause the leaves to wilt and can lead to the death of the plant if the mites are not eliminated. Even if the plants are not killed, growth is frequently stunted as the host tries to compensate for the cell tissues the mites feed on.
There are two varieties of red spider mite, but they both go through the same basic life process as black spider mites. Females lay eggs on the host plant, which then hatch into six-legged larvae. When these larvae molt, they gain their other two legs. Two molting processes later, the red spider mites mature into adults. This process usually takes several weeks from start to finish.
The southern red spider mite is found on many plants, but the European red mite usually prefers apple trees. The southern red mite can easily be brought into the home on new houseplants, which it often infests. There are many more spider mites, but only the European and the southern are completely red.
Red spider mites can be difficult to eliminate, but need to be looked after quickly before the mites can spread to other plants. Washing plants and removing any webs can get rid of a red mite population, but this may need to be done repeatedly until there are no more signs of adult mites. Red spider mites thrive in dry conditions, and misting the leaves of other plants in the area can help discourage the spread of the pests. For outside infestations, releasing insects like ladybugs and lacewings to feed on the mites can be an effective method of control. Pesticides that will kill these natural predators should not be used because these good insects are such an effective method of controlling red spider mites.