Spider mites are the most common plant pest, and they can quickly devastate a garden. But spider mites don’t mean that all hope is lost for your plants. They are relatively easy to remove from a garden using inexpensive products that you can find at any home and garden store. In this post, we discuss how you can save your plants from spider mites with simple treatments and preventative measures.
Spider mites have a few natural predators that can help control spider mite populations. Spiders, ladybugs, minute pirate bugs, and lacewing larvae will eat spider mites. But there are also commercially available chemicals that kill spider mites on contact.
Spinosad is one of the most common insecticides used against spider mites. It is sold under the brandname Monterey Garden Insect Spray and Ferti-lome Spider Mite Killer Concentrate.
These products are widely available at garden supply stores and nurseries, and they are very effective in controlling spider mites in vegetable gardens and ornamental gardens.
The most important thing to remember about using insecticidal soaps and sprays is that they do not kill spider mites. They simply slow down the growth of spider mites, making them unable to reproduce as quickly.
You should use these products only if you have a few spider mites that are noticeable on your plants. After you have applied the insecticidal soap or spray, wait several weeks before planting again.
You will find that your plants’ health returns to normal after you have waited for a few weeks since treatment.
Many people find it easier and more economical to purchase a ready-to-use pre-emergent spray formulated for use in their vegetable garden or flower beds.
These ready-to-use sprays are typically formulated with an insecticide and a fertilizer, such as rose food. These products kill the eggs of adult spider mites along with weed seeds that have not yet sprouted in the garden.
If you decide to use a ready-to-use pre-emergent spray against spider mites, spray your plants once in spring before the plants begin growing, and then again if you still see spider mites in your vegetable garden or flower beds after your plants have grown another few inches.
Home gardeners often use an environmentally friendly method called solarization to control plant pests like spider mites without using any chemicals at all. Solarization is a simple method that prevents spider mites from reproducing by extreme heat. All you have to do is place a tarp or plastic over the plants before the sun comes out.
This treatment is best used in late spring when the ground is still cool. Plants that are still young and tender can malnourish and die if they are not protected from the sun.
The next step in controlling garden pests like spider mites is to use proper cultural practices to enhance growth and combat disease. In particular, healthy plants benefit greatly from good drainage, good air circulation, plenty of moisture, adequate soil nutrients, and proper fertilization of your vegetable garden or flower beds.
Repotting plants that are suffering from spider mites is never recommended. If you see plant pests like spider mites on your plants, it is probably a good idea to repot them and replant them in a new soil. The old soil will have a large population of eggs and immature spider mites that will not survive when you replant your plants.
The best way to prevent spider mites is to practice good garden sanitation techniques. Remove plant debris and dead leaves at the end of the season and do not let it accumulate next to your vegetable garden or flower beds.
You should also cover your patio furniture or benches with sheets or tarps when they are not in use so that they remain clean as well.
How to Find Spider Mites on Houseplants and Outdoor Plants
Mite-damage symptoms mimic other plant diseases or injuries, making it difficult to know whether your plant has an insect problem or a disease. In addition, mites also cause damage to their host plants in ways that are difficult to distinguish from other problems.
Because this species is so widespread and well known, it is often mistaken for other pests or diseases—such as spider mites or fungus gnats. Look for silk like threads or webbing that covers leaves, and the mites themselves on the undersides of leaves. Unlike spider mites, fungus gnats are not found on the undersides of leaves.
Mites are small by insect standards and vary greatly in coloration, depending on their species. Most houseplant mites are microscopic and easily mistaken for common pests like aphids or white flies. They have eight legs in lieu of antennae, which makes them look like spiders with tiny bodies. Mite damage is evidenced by stippled or otherwise discolored growth on houseplants and outdoor plants.
- Dark brown spider mite adults are tiny insects about 3/32 – 3/16 inch long. They are found all over the plant but most common on leaves and stems above the soil line.
- Spider mites have pale legs and a broad body. The adults are covered with fine hair and resemble tiny spiders. At rest, they hold their two front legs up like antennae, but when moving they raise their whole front bodies from the ground.
- The female is dark red to purple, sometimes brown, and has eight legs; the male is yellowish orange or light greenish yellow and has six legs. They are usually found on the same plants as spider mite eggs or their excrement, which resembles fine dusting of mold (they leave yellow spots when crushed).
- The egg sacs look like tiny light-colored balls made of silk that are cemented to plant material.
- Webbing is made by the female spider mite while she is feeding to protect her eggs or young.
- Place plants in a well-ventilated area where mites cannot be blown off by the wind. The infested plants should be removed and destroyed. Foliar sprays and soaps are not effective against spider mites on houseplants, and should never be used on outdoor plants.
- Be sure to examine all the plants in your house or greenhouse. Insecticidal soaps, oil sprays, and other pesticides registered for use against spider mites are the safest choice for indoor plants. Apply them as a fine spray to thoroughly cover all surfaces of the plant, including both top and bottom of foliage and stems. Apple cider vinegar spray also works well as a natural spray given the highly acidic content that plant pests such as spider mites do not like.
- No pesticide or drug is 100% effective. Repeat applications may be necessary every 2-3 days until symptoms disappear. Wash out spray equipment with hot water between treatments to prevent transferring mites from one plant to another.
- For outdoor plants, you can release ladybugs as they feed on insects such as spider mites.
How to prevent spider mites
- Keep houseplants out of direct sunlight.
- Frequent waterings keep foliage dry and discourage mites from establishing a colony.
- Don’t overcrowd plants by allowing more than one plant to grow together, as this creates an ideal environment for spider mites to thrive. Direct sunlight helps to discourage spider mite outbreaks even if the plants are crowded. Therefore, place plants in a well-ventilated area where spider mites cannot be blown off by the wind.
- High humidity and temperatures encourage spider mites.
- Take good plant care, allowing the plant itself to boost its own defense mechanism against pests and disease. Feed them regularly with a balanced fertilizer, and don’t let foliage grow too dark or too light.
- Regularly check plants for any signs of pest infestation. If visible signs are present (see references below), both chemical and natural methods should be used at the same time.
Where Do Spider Mites Come From?
Spider mites are small, white, soft-bodied insects that hatch from eggs laid in tiny weblike egg sacs. The mites feed on the leaves, often causing leaves to wilt or turn yellow.
They suck the plant’s nutrients causing stunted foliage and sometimes death of the plant. Female mites can eat their way through a leaf’s compounds and tissue, eventually causing it to die.
Spider mite infestations are not caused by poor garden maintenance or by inadequate fertilization. Spider mite infestations originate from leaf surfaces that have been covered with many tiny web threads which have collected there from other areas of the plant where they have been feeding on aphids and other insects at night.