Cyclamen and broad mites

Overview

Cyclamen and broad mites are microscopic mites (less than 0.02mm in length) that deform and distort the growing tips of plants which can result in stunted tips, curled leaves, and lack of flowering. Cyclamen mites can be a pest of garden strawberry plants and both can be serious pests of a wide range of plants including African violet, cyclamen, begonia, snapdragon, impatiens, gerbera, ivy, and many indoor tropical plants.

Cyclamen mites on Strawberries

Steneotarsonemus pallidus, or cyclamen mites, can be major pests on strawberries. Plants they infest are chlorotic and sickly looking because mites extract chlorophyll from the plants. Yellow or white stippling appears on leaves. New growth is stunted and older growth becomes distorted and curled. Flower buds may drop. Fruit that develops from infected buds are small and dry. Whole plants may have a bronze cast.

Symptoms and Diagnosis

The mites are generally not detected until after they have caused significant damage and then only with the aid of a dissecting microscope. Hand lenses are usually not powerful enough to see these small mites. Mites are closely related to spiders and likewise adults have 4 pairs of legs. Larvae, however, have only 3 pairs.

Cyclamen mites are usually greenish and transparent and less than 1 mm in size. Their eggs are smooth and more apt to be found hidden in folds of plant tissue. They like to hide in buds or tips of new growth. They avoid light and prefer high humidity and cool (60^oF.) temperatures. Their feeding results in stunted growth with leaves generally curling upward. Leaves become stiffened and brittle (black in the case of delphiniums) and flowers are deformed or reduced.

Broad mites are smaller than cyclamen mites, broader, and faster moving. Adult females are straw-colored. Broad mites have a white stripe down their back, but the easiest way to differentiate the two may be by their eggs. Broad mite eggs have many small white bumps on them and are usually observed in more open locations. Typically adults cause deformed shoots and leaves, which usually curl downward, and reduced flowering. Bronzing or purpling of the leaves commonly occurs on the underside of leaves where the mites feed. Broad mites reproduce most prolifically at temperatures between 70 and 80^oF.

Lifecycle

Cyclamen mites can complete their lifecycle in only 1 to 3 weeks depending upon conditions. Adults can overwinter out of doors as far north as Canada in protected locations and complete many generations a year.

Broad mites can complete their lifecycle in only one week and also have a resting, pupal stage. They can overwinter in greenhouses or on indoor plants but is doubtful they can overwinter out or doors in Missouri. Meaning that each year new infestations out of doors develop from plants that have been overwintered indoors or from infested plants obtained from a nursery or garden center.

Integrated Pest Management

1. Dispose of infested plants. Since these mites can be difficult to control and reproduce rapidly, disposing of infested plants is often wise.

2. Sanitation. Examine newly purchased plants in the spring and reject them if they have curled or deformed tips and shoots that may be signs of mites.

3. Heat treatment. Cyclamen and broad mites are heat sensitive and can be killed if immersed in 110^oF water for 30 minutes. These temperatures are generally low enough to cause little damage to most plants but water temperature must be maintained properly and the whole plant, pot and all, needs to be immersed. Removing heavily infested shoots first may make this process easier.

4. Treat with miticidal/ insecticidal soap or horticultural oil. To be effective the spray must completely cover the insects so apply liberally and make sure the spray reaches under leaves and into shoot tips where the mites hide.

5. Use chemical sprays. Some pyrethroid insecticides are registered for use against cyclamen/broad mites. Be sure to read and follow label instructions.

Organic Strategies

Strategies 1, 2, and 3 are strictly organic approaches. For an organic approach to Strategy 4, consult the Organic Materials Review Institute (OMRI™) for appropriate insecticidal soap products.

Pesticide Disclaimer: 

Always follow the product's label and ensure the product is effective against cyclamen & broad mites. Not following the pesticide label before usage is a violation of federal law.