Broad Mites Vol. 2, No. 16

Filed Under:

Insects, Ornamental Plants, Insects Vegetable Gardens

June 14, 2016

Polyphagotarsonemus latus

Order: Acari
Family: Tarsonemidae

What’s wrong with this pepper? Looks like some sort of herbicide injury or nutrient deficiency, or possibly some type of virus, but it’s not. These symptoms are caused by broad mites. The saliva they inject into the plant when feeding causes this unusual distorted growth. Broad mites concentrate their feeding in new growth, and it does not take very many to cause damage. Fortunately, broad mites are relatively uncommon pests of vegetables and greenhouse ornamental plants. Because they do not survive well outdoors during the winter months, infestations are most common in greenhouses and indoor plants, or on transplants that were started in a greenhouse.

In peppers, damage may not become obvious until plants have been transplanted and begun to set fruit. Russet-colored, rough-skinned fruit is a key symptom of heavy broad mite infestations on peppers. Also note the distorted, strap-like leaves. This is a typical symptom of broad mite injury on pepper and many other plants. Heavily infested plants may also exhibit russeting on leaves and stems, and have stunted, distorted growth. Why don’t you see any mites? Broad mites are considerably smaller than spider mites, too small to see without some type of magnification, preferably a good microscope.

Broad mites attack a wide range of vegetable and ornamental plants, and even some woody ornamentals like azaleas and hibiscus. Their host list includes peppers, tomatoes, beans, and cucumbers, as well as New Guinea impatiens, impatiens, begonias, gerbera daisies, zonal geraniums, chrysanthemums, and a few dozen other herbaceous ornamentals. Damaging infestations are most often seen on peppers, impatiens, and begonias, as well as African violets and cyclamen. These last two plants are also frequently attacked by cyclamen mites, which are similar to broad mites, cause similar damage, and attack many of the same plants.

Control: Remove and destroy heavily infested plants, taking care to avoid spreading mites to other nearby susceptible hosts. Commercial nurserymen can choose from several commercial miticides, but it is important to read the label and make sure the product is specifically labeled for broad mites, because some miticides do not control broad mites. Miticides containing active ingredients that have translaminar activity, such as abamectin, chlorfenapyr, or spiromesifen, are most effective. Make at least two successive applications 7 to 10 days apart.

There are no specific miticides available for control of mites in home vegetable gardens. Home gardeners can remove and destroy infested plants and spray surrounding susceptible plants with bifenthrin (Ortho and Monterey products), insecticidal soap, or horticultural oil. Thorough coverage and repeated treatments are needed because none of these treatments work systemically.

Blake Layton, Extension Entomology Specialist, Mississippi State University Extension Service. The information given here is for educational purposes only. Always read and follow current label directions. Specific commercial products are mentioned as examples only and reference to specific products or trade names is made with the understanding that no discrimination is intended to other products that may also be suitable and appropriately labeled.