Cyclamen Mite Management in Organic Strawberries
Cyclamen mites (Phytonemus pallidus) thrive in humid locations and are a common greenhouse pest. They are also serious pests of both conventional and organic strawberries, especially in perennial matted row systems.
The first step in managing cyclamen mites is accurate and early diagnosis of the symptoms they cause on plants. Cyclamen mite feeding causes wrinkled, distorted leaves, slightly darker in colour than uninfested leaves (Figure 1). When populations are low, leaves grow to nearly full size, but may be crinkled or roughened. Leaves heavily infested with cyclamen mites become severely stunted and crinkled, resulting in a compact toughened leaves in the center of the plant (Figure 2, Figure 3). Fruit on infested plants is small, bronzed, with prominent seeds. When uncontrolled, this mite can prevent new growth and severely affect fruit quality.
Figure 1: Wrinkled and distorted leaves of strawberry caused by cyclamen mites.
Figure 2 and 3: Stunted and crinkled leaves of strawberry resulting from a severe infestation of cyclamen mites.
This problem is easy to confuse with other problems. Both cyclamen mite and winter injury can cause plants to be stunted and slow to grow in spring.
Symptoms are also somewhat similar to those caused by virus disease or calcium deficiency.
To confirm the diagnosis of cyclamen mite injury, it is important to see the mites. Cyclamen mites are tiny (< 0.3 mm) oval mites, white to amber in colour and best viewed with 10- 40x magnification (Figure 4). Eggs are oval, translucent and comparatively large, about half the size of an adult mite. Masses of eggs in crevices of leaves look like piles of salt (Figure 5). At low population densities, they are found mainly along the midrib of folded leaves and under the calyx of the fruit. At higher population densities, they can be in any protected part of the plant. This mite prefers high humidity. When the leaflet unfolds, changes in temperature and humidity cause the mites to migrate down the petiole to new leaflets.
Figure 4: Cyclamen mite (white to amber in colour) and egg viewed under magnification.
Figure 5: Cyclamen mite eggs are oval, translucent and approximately half the size of adult mites.
Mites can be introduced to new fields on infested planting stock. Infestations may first appear in scattered locations. As populations build up, mites move to new plants along the runners. The mites also may be transferred from plant to plant by routine cultural practices, by drafts of air, by close proximity of plants, or on clothes or hands. Female cyclamen mites produce hundreds of eggs; one mite can soon produce a mite colony large enough to cause damage and spread to surrounding plants. Older fields are more likely to have higher populations of cyclamen mite. There are multiple generations each year but populations peak in early spring (bud- green fruit stage) and again in late summer (late August- September).
For more information on cyclamen mites, see OMAFRA's crop IPM modules at www.Ontario.ca/cropipm
For more information:
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