Organic Spider Mite Remedy for Hibiscus

Drowning

• Drown spider mites by immersing your hibiscus in a bathtub or sink of water that’s 90 degrees Fahrenheit. Wrap your plant in pantyhose, a pillowcase or a large sock first. Make sure that plants are completely covered with water, and weigh them down to keep them submerged. Leave plants covered for 45 to 60 minutes. Make sure that the water isn’t too hot, and don’t leave the plants in too long or you’ll damage your plant. Properly done, this method should kill all spider mites with one treatment.

Spraying

• If your hibiscus is too large to submerge, or if it’s planted in the ground, you can wash spider mites off your plant by aiming a hard stream of water at the leaves. Every part of the plant must be sprayed, especially the undersides of leaves where spider mites like to congregate. Spraying your hibiscus will remove adult mites but not all the eggs or nymphs, so this method has to be repeated three or four times at intervals of five to seven days.

Horticultural Oil

• Horticultural oils are often made from crude oil, but several brands of organic oils are derived from plants such as soybean, canola or cottonseed. Both cottonseed and soybean are fairly effective. Canola and sunflower oils work but not as well. These oils kill spider mites by smothering them and, according to the Colorado State University Cooperative Extension, are the most effective way for home gardeners to treat spider mites. Horticultural oils shouldn’t be applied when temperatures are above 90 degrees Fahrenheit. Use a respirator mask when spraying because breathing the oil can hurt your lungs. Treatment should be repeated.

Neem Oil

• Neem oil is derived from the neem tree, which is native to southern Asia. The seeds of this tree contain several compounds that are insecticidal, including azadirachtin, which acts as an insect growth regulator, causes spider mites to stop feeding and keeps them from laying eggs. Although it will reduce the number of spider mites on your hibiscus, it won’t completely eliminate the problem.

Pyrethrum

• Pyrethrums are natural insecticides derived from the dried flower heads of the pyrethrum daisies including Chrysanthemum cinerariaefolium and C. coccineum. These insecticides have a low toxicity and work fast, but they’re only effective for a few hours. They will reduce spider mite numbers, but they aren’t very effective by themselves for controlling these pests. Some pyrethrum products contain nutmeg, parsley, sassafras or safrole oil to help them work better. Don’t confuse pyrethrums with pyrethroids, which are synthetic chemicals not approved for organic use.

Predators

• Several species of insects feed on spider mites, including predator mites and a species of dark-colored lady beetle. Minute pirate bugs, big-eyed bugs, predatory flies, lacewings and predatory thrips are also natural enemies of spider mites. Predatory insects can be purchased from garden supply stores, or you can encourage naturally occurring predators by reducing dust around your hibiscus plants and by not using insecticidal sprays.