How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PEST

At low population densities, cyclamen mites are usually found along the midvein of young, unfolded leaves and under the calyx of newly emerged flower buds; when populations increase, these mites can be found anywhere on nonexpanded plant tissue. They are not visible to the naked eye, and when mature they measure only about 0.01 inch long. Mature mites are pinkish orange and shiny. The hind legs are thread- or whiplike in the female and grasping or pincerlike in the male. Eggs are translucent and comparatively large. Adult females lay about 90 eggs, 80% of which develop into females. During summer, newly hatched mites develop into mature adults within 2 weeks. Populations build rapidly soon after a field becomes infested. Cyclamen mites overwinter as adult females in the strawberry crown and can be present on transplants if the nursery field was infested.

DAMAGE

Cyclamen mites are primarily pests in fall-planted and second-year plantings, but they can be transplanted into first-year fields and the damage symptoms become apparent on leaves as the season progresses. Leaves heavily infested with cyclamen mites become severely stunted and crinkled, resulting in a compact leaf mass in the center of the plant. Feeding on flowers can cause them to wither and die. Fruit on infested plants is dwarfed, and the seeds stand out on the flesh of the berry. When uncontrolled, this mite can prevent plants from producing fruit.

MANAGEMENT

Management of cyclamen mite requires carefully timed sprays of miticides that do not harm natural enemy populations. Prevent its introduction into strawberry fields by following good cultural practices. Propagating nursery stock free of cyclamen mites is essential to prevent introducing populations to fruit-producing fields.

Biological Control

Two naturally occurring predatory mites of cyclamen mite are Typhlodromus bellinus and T. reticulatus, but their populations build up too slowly to provide economic control. Early season releases of the commercially available predatory mite, Amblyseius californicus, may be able to control this pest mite. Amblyseius cucumeris releases have not proven to be effective.

When pest populations become large, the sixspotted thrips, minute pirate bugs, and western predatory mite (Galendromus occidentalis) all feed on cyclamen mites.

Cultural Control

Cyclamen mites can easily be transferred from one location to another by pickers, bees, birds, and equipment, including strawberry freezer trays. It may be worthwhile to dip trays in a hot water bath to prevent infestation. Infested nursery plants are the major source of this pest in annual plantings; be sure to use uninfested nursery stock. When transplants are known to be infested, treat them in hot water at 100°F for 30 minutes before planting. Avoid second-year plantings in problem areas. To slow the spread of infestations, rogue infested plants as soon as symptoms appear.

Organically Acceptable Methods

Biological and cultural control methods are acceptable for use on organically certified strawberries.

Monitoring and Treatment Decisions

If any damage symptoms are observed, be sure to monitor the rest of the field carefully to determine the extent of the infestation. Monitor newly unfolding leaves and treat the area of the field believed to be infested when densities of one cyclamen mite in 10 leaves are found. To control cyclamen mites, a high rate of water per acre (300-500 gal) is necessary to soak the unfolded leaves and immature flower buds located in the crowns. Effective control requires a high rate of kill because populations of this mite can increase rapidly. Roguing and treating infested hot spots with a hand-sprayer can be useful in suppressing infestations without having to treat the entire field. In nurseries, early season control before plant canopy closes over is critical.

PUBLICATION

UC IPM Pest Management Guidelines: Strawberry
UC ANR Publication 3468
Insects and Mites
F. G. Zalom, Entomology, UC Davis
P. A. Phillips, UC IPM Program, UC Cooperative Extension, Ventura Co.
N. C. Toscano, Entomology, UC Riverside
M. Bolda, UC Cooperative Extension, Santa Cruz Co.

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