Recognize The Signs
Spider Mites are not insects, but tiny arachnids related to Spiders and Ticks. They are very small and nearly invisible to the naked eye. Under a microscope or magnifying glass (a very helpful tool), you'll see four pairs of legs, no antennae, and a single, oval body.
Sometimes easier to see are the fine silk webbing many spider mites leave on plants. They usually congregate on the undersides of the leaves, and if the infestation is severe, that’s where you’ll see the webbing first. It can coat the foliage, collect dust and make the whole plant look dirty.
Which plants at risk?
Spider Mites like it warm and dry – precisely what it's usually like outside in the heat of the summer, and inside many homes in winter. They like dusty, drought-stressed plants, so it helps to spray outdoor plants with water, frequently wipe down houseplant leaves with a damp cloth and water regularly. Learn more information on How To Clean Plants.
The damage they do
Spider Mites have tiny mouthparts ideal for piercing and sucking the juices from leaves. At first, you’ll notice a silvery, shiny stippling or dry, dusty look to the leaves. Gradually, they turn bronzed or yellowish with an increased silvery sheen, then drop off. Heavily infested plants are often stunted or even killed.
Give plants the shake test
A good way to confirm the presence of Spider Mites is to hold a piece of white paper under a branch or leaf, and give a good shake or a hard flick with your finger. If you see any tiny, moving specks on the paper, you probably have spider mites, although thrips can look similar at first. Confirm your diagnosis with a magnifying glass.
There are many beneficial insects, such as Lacewings and Lady Beetles, that prey on Spider Mites. The most commonly sold predators are actually other types of Mites. Predatory Mites can be purchased and released onto infested plants. Specialty mail order catalogs are the best sources and provide thorough information on how to successfully use predatory mites. Be sure you know which species is appropriate. Some predatory mites are host specific or better under different weather conditions. If you try beneficial insects, avoid applying pesticides that could kill them.
Remember, Spider Mites are not true insects and often cannot be controlled with many traditional insecticides. Be sure to check the pesticide label to see if Spider Mites are mentioned specifically or it is designated "miticide”. Most Spider Mites can be controlled with horticultural oils, including Natria Neem Oil, and soaps, such as Natria Insecticidal Soap. Sulfur-based sprays, such as Natria Insect, Disease & Mite Control are also effective. These usually can be applied in the heat of summer, but be sure to check the label for application or temperature restrictions. Make sure to treat both upper and lower surfaces of the leaves for best results.