Managing Cyclamen Mites and Broad Mites in the Greenhouse
with new images January 2005

Tarsononemid mites including the cyclamen mite (Phytonemus pallidus) (Banks)) and the broad mite (Polyphagotarsonemus latus) (Banks)) can cause serious damage to a variety of greenhouse crops. These mites are extremely small which makes it difficult to detect the mites before severe feeding damage is evident.

Description

Cyclamen mites were first reported as a pest in the United States in 1898. Adult mites are very small, less than 1/100 of an inch long, and cannot be seen without the aid of a microscope. They also tend to hide in dark, moist areas within tender buds or deep within the flower further hindering detection. Cyclamen mites are shiny and elliptical in shape with four pair of legs. Females are translucent yellow-to-orange whereas males are light brown with a claw on each back leg. Broad mites are slightly smaller than cyclamen mites and are colorless-to-pale brown with a white stripe down the center of their backs.

One way to distinguish cyclamen mites from broad mites is by the egg stage. Cyclamen mite eggs tend to be laid in dark, moist areas. Eggs are smooth, elliptical and about 1/2 the size of the adult female. Broad mite eggs are elliptical but are covered by small whitish bumps that look like rows of diamonds. Broad mite eggs tend to be laid so they are more exposed on the underside of the leaf or stem surface than cyclamen mite eggs.

Broad mite injury on impatiens - click for larger image
Broad mite injury on New Guinea Impatiens
photo by Leanne Pundt
Broad mite injury to salvia - click for larger image
Broad mite injury to salvia.
Note downward cupping of leaf edges
photo by Leanne Pundt
 
Cyclamen mite injury on delphinium - click for larger image
Cyclamen mite injury on delphinium
Note blackening of buds that may resemble a bacterial disease.
photo by Leanne Pundt

Feeding Damage

Cyclamen mites prefer to feed in buds and young leaves. Leaves curl inward and develop a puckered appearance. Pit-like depressions can also form. Leaves may become brittle or appear streaked. Flowers can become shriveled and discolored. Sometimes, flower buds may not open at all.

Cyclamen mites have a broad host range and can feed on African violets, cyclamen, dahlia, gloxinia, ivy, snapdragons, vinca, chrysanthemum, geranium, fuchsia, begonia and petunia. Outdoors, the cyclamen mite can attack delphinium, aconite, chrysanthemum, verbena, strawberry and viola. Damage to delphinium is particularly severe, as flower stalks become twisted and buds turn black and do not open.

Broad mites inject a toxin from their saliva as they feed. Leaves become twisted, hardened and distorted with bronzed lower surfaces. Young terminal buds can be killed. Leaves frequently turn downward.

Broad mites have a wide host range and can feed on African violets, ageratum, begonia, cyclamen, dahlia, gerbera, gloxinia, hibiscus, ivy, jasmine, impatiens, New Guinea impatiens, lantana, marigold, snapdragon, verbena, and zinnia. Broad mites can also infest vegetable bedding plants such as beans, peppers and tomatoes.

Life Cycle and Biology

High relative humidity (80 to 90%) and temperatures of 60oF favor the development of cyclamen mites. Severe outbreaks may occur in greenhouses in the fall and winter months. Females may live for up to one month and can reproduce without mating. Cyclamen mite females lay 2 to 3 eggs per day for up to two to three weeks. The eggs are deposited in moist, dark places in crevices and at the base of the plant. Cyclamen mite eggs are oval, smooth and about one half the size of the adult female. Most of the eggs will develop into females. Larvae hatch from the eggs in 3 to 7 days. The slow-moving, white larvae feed for 4 to 7 days. Adults emerge from the pupal stage in 2 to 7 days. Their life cycle varies from 1 to 3 weeks depending upon greenhouse temperatures. Outdoors, the adult female can overwinter in protected locations as far north as Canada.

High temperatures of 70o to 80o F favor the development of broad mites. Female broad mites lay from 30 to 75 eggs on the leaf surface over an 8 to 13 day period. Larvae hatch in 2 to 3 days and begin feeding. Adult and larval broad mites tend to be faster moving than cyclamen mites. Broad mites can complete their life cycle from egg to adult in as little as one week's time.

Monitoring

Both broad and cyclamen mites are too small to be seen without the aid of a microscope. Regular inspection of crops for their feeding damage is the best way to detect infestations. Tarsonemid mites tend to avoid light and are found in the crown of host plants. Cyclamen mites feed in the young, developing buds whereas broad mites feed on the underside of leaves. If characteristic symptoms are seen, send samples to a diagnostic laboratory that can inspect samples under a microscope.

Management

Rogue infected plants as soon as possible. If detected early, it may be feasible to discard a small number of infested plants. Tarasomid mites can be easily spread to healthy plants by workers' hands or clothing. During scouting and other routine tasks, enter mite-infested areas last.

Biological Control

A number of different species of predatory mites have been reported to feed upon cyclamen mites in strawberry crops. It has not yet been determined whether these mite species are effective against cyclamen mites in greenhouse crops. The predatory mite, Neosililus barkeri, has been successfully used against broad mites on peppers.

Chemical Control

A number of different miticides are labeled for both cyclamen mites and broad mites. High volume applications and repeat applications are frequently necessary to achieve adequate control. For more information on the specific materials to apply, see the latest edition of New England Floricultural Recommendations: A Management Guide for Insects, Diseases, Weeds and Growth Regulators.

Leanne Pundt, University of Connecticut, Extension Educator, Commercial Horticulture

References:

Baker, J.R. 1994. Insects and Related Pests of Flowers and Foliage Plants. Some important, common and potential pests in the southeastern United States. North Carolina Cooperative Extension Service. 105 pp.

Baker, J. R. 1997. Cyclamen Mite and Broad Mite. North Carolina Cooperative Extension Service. Ornamentals and Turf Insect Note 28. 2pp.

Gilrein, D. 1998. Cyclamen mite is back. GrowerTalks. January 1998. 59.

Lopes, P. and L. Stack. 2001. New England Greenhouse Floricultural Recommendations. A Management Guide for Insects, Diseases, Weeds and Growth Regulators. New England Floriculture, Inc. Pocassett, MA.

Westcott, C. 1974. The Gardener's Bug Book. 4th edition. Doubleday and Co. Garden City, NY 689 pp.

Information on our site was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.

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