While much rarer than the twospotted spider mite in North Carolina, cyclamen mites (Phytonemus pallidus, Acari: Tarsonemidae) can cause significant problems in strawberries when they do occur. Since 2021, severe infestations with cyclamen mites have been reported in some strawberry farms in North Carolina and Virginia. However, these infestations are sporadic and often originate with infested nursery seedlings.

Adult cyclamen mites are about 0.25 mm long and require a 20X hand lens or dissecting microscope to detect them. As these mites thrive in humid conditions, they can be a problematic greenhouse pest. However, they can also be found in the field, usually originating from contaminated nursery stock. Adult female mites lay oblong eggs on strawberry leaves that hatch into tiny, white, six-legged larvae. They have eight legs once they reach adulthood. Adult mites are pear-shaped and a translucent, creamy orange color. The adults show sexual dimorphism (different sexes of the same organism look different). In males, the final pair of legs end in a claw like structure. In females, the final pair of legs are skinny with a long hair protruding from the tip. The entire life cycle of the cyclamen mite is less than three weeks so, once established, populations can build rapidly.

When originating from nursery stock, cyclamen mites usually overwinter in few numbers on the developing plants and resumen reproduction in spring when temperatures are above 50 ºF. Infestations are usually detected in March or April when large populations are present.

Cyclamen mites use their piercing-sucking mouthparts to feed on plant material. These mites usually established in folded, tiny, developing leaves close to the crown of the plant. When large populations are established, cyclamen mites can be found feeding on young unfolded leaves. However, symptoms of infestation can be found throughout the plant. Infested leaves will appear stunted and crumpled, flowers will wither, and fruit will be shrunken with protruding seeds. By the time these symptoms appear in spring, it is too late to limit damage, so cyclamen mites must be managed with the mindset of prevention. Treatments should be applied when 1 leaf in 10 shows cyclamen mite infestation.

Stunting and leaf deformation associated with cyclamen mite damage in strawberry.

Jody Fetzer, Maryland National Capital Park and Planning Commission, Bugwood.org

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Stunting and leaf deformation associated with cyclamen mite damage in strawberry.

Jody Fetzer, Maryland National Capital Park and Planning Commission, Bugwood.org

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Stunted strawberry plant due to severe cyclamen mite infestation in open field strawberries. Surrounding plants look healthy but were confirmed to have smaller populations of cyclamen mites.

Photo by L. Lopez

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Stunted strawberry plant due to severe cyclamen mite infestation in open field strawberries. Surrounding plants look healthy but were confirmed to have smaller populations of cyclamen mites.

Photo by L. Lopez

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Cyclamen mite infestations in North Carolina are usually due to contamination of transplants at the nursery. Transplants should be checked for cyclamen mites with a 20X hand lens or dissecting microscope before adding to them to the field or greenhouse. Cultivar susceptibility may vary, with ‘Ruby June’ showing more susceptibility to to cyclamen mite infestations in field studies in 2022 and 2023 in VA (Lopez unpublished data), while ‘Chandler’ and ‘Albion’ are usually observed with larger populations of TSSM. Scheduling monitoring efforts every two weeks during planting and dormancy, and weekly during warmer conditions, ensures timely intervention.

Conventional Miticides

Conventional miticides are available to control this pest. Because cyclamen mites are established deep in the crown of plants in folded leaves, reaching these areas with contact insecticides may be challenging. Thus, high volume applications at standard presure may improve control. Cyclamen mite control is more limited since only three miticides are registered for this pest. Spring applications are advised for cyclamen mite management only if the presence of these mites is confirmed. Applications against cyclamen mites are not advised if their presence is not confirmed or during the fall or winter, as mite numbers usually do not reach action thresholds until spring.

For commercial recommendations in North Carolina see the North Carolina Agricultural Chemicals Manual, and see the Southern Region Small Fruit Consortium Strawberry IPM Guide for regional recommendations. For control recommendations for areas outside of the southeast, please check with your local extension agent.

Biological Control

Releases of the predatory mite Neoseiulus californicus (Acari: Phytoseiidea) have shown to be effective in controlling cyclamen mites in CA, FL, and VA. These predatory mites have been observed feeding on cyclamen mite infested strawberries in Virginia in 2022 and 2023 open field trials. Predatory mites can reach the depts of the strawberry crowns where cyclamen mites established. When severe infestations are encountered, a combination of miticides and predatory mites is prefered to manage cyclamen mites.

Cyclamen Mite in Virginia Strawberries - Virginia Tech

Guidelines for purchasing and using Commercial Natural Enemies - University of Florida

Cyclamen Mite - University of Florida Entomology and Nemotology

Strawberry Cyclamen Mite - UC IPM

North Carolina Agricultural Chemicals Manual

Strawberry IPM Guide - Southern Region Small Fruit Consortium