Beginner

Scientific Name
Phytonemus pallidus

Identification

• Mites are tiny (< 0.3 mm or 1/100 in.), oval shaped and white to amber in colour
  
• Eggs are oval, translucent and fairly large, about ½ the size of a mature mite
  
• Masses of eggs in crevices of leaves look like piles of salt.
  
• Feeding causes wrinkled, distorted leaves, slightly darker in colour than uninfested leaves
  
• Heavily infested leaves become severely stunted and crinkled, resulting in a compact leaf mass in the center of the plant
  
• Fruit is small, bronzed, with prominent seeds

Often Confused With
Winter injury
Lontrel damage
Viruses
Calcium tip burn

Period of Activity
There are multiple generations each year but populations peak in early spring (bud- green fruit stage) and again in late summer (late August- September).

Scouting Notes
Monitor strawberry fields when new buds emerge from the crown and continue until harvest. Expect more problems in older fields. Walk a large portion of the field and look for areas where the plants are slightly stunted and leaves are somewhat distorted or crinkled. Confirm the presence of cyclamen mite by pinching out the newest leaves in the crown. Unfold these leaves and examine the mid vein and lower leaf where it joins the petiole. Magnification is needed for identification of these mites. Scout fields again in late summer for cyclamen mite damage.

Thresholds
None established in Ontario.

Advanced

Scientific Name
Phytonemus pallidus

Cyclamen mites thrive in humid locations and are a common greenhouse pest. They are also a serious pest of strawberries.

Identification
Mites (mature and immature): Tiny (< 0.3 mm or 1/100 in.), oval, white to amber in colour and best viewed with 10- 40x magnification.

Eggs: Cyclamen mite 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.

Damage: Cyclamen mite feeding causes wrinkled, distorted leaves, slightly darker in colour than uninfested leaves. 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 compact toughened leaves in the center of the plant. Fruit on infested plants is small and bronzed, with prominent seeds. When uncontrolled, this mite can prevent new growth and severely affect fruit quality.

Often Confused With
Winter injury (Both cyclamen mite and winter injury can cause plants to be stunted and slow to grow in spring.)
Lontrel damage (Residual soil applied herbicides may stunt plant growth. Phenoxy-type herbicides can cause leaf distortion. With damage from phenoxy herbicides, the plant grows out of the injury and newer leaves are not affected.)
Viruses (Crinkled and distorted leaves resemble some virus symptoms.)
Calcium tip burn (Calcium deficiency affects the tips of new leaves, causing leaf distortion.)

Biology
Cyclamen mites overwinter as adult females in the strawberry crown. 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. There are multiple generations per season. Newly hatched mites develop into mature adults within 2 weeks if temperatures are favourable. Populations build rapidly soon after a field becomes infested, and tend to peak in late spring and again in early fall.

Mites can be spread to new fields on infested planting stock. 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. Females can produce eggs in absence of males; one mite can soon produce a mite colony large enough to cause damage and spread to surrounding plants.

Period of Activity
There are multiple generations each year but populations peak in early spring (bud- green fruit stage) and again in late summer (late August- September).

Scouting Notes
Expect to find more problems in older fields. Monitor strawberry fields when new buds emerge from the crown and continue until harvest. Walk a large portion of the field and look for areas where the plants are slightly stunted and leaves are somewhat distorted or crinkled. Confirm the presence of cyclamen mite by pinching out the newest leaves in the crown. Unfold these leaves and examine the mid vein and lower leaf where it joins the petiole. Masses of eggs look like piles of salt. Magnification is needed for identification of these mites.

Scout for cyclamen mites again in late summer (August- September) and make note of problem areas for control early the following spring.

Thresholds
None established in Ontario.

Management Notes

• Successful application of an insecticide or miticide for cyclamen mite control depends on thorough coverage and a high volume spray.
• Water volumes of 4000 L/ha are recommended.
  
• The best timing for control is when there is little leaf canopy: spring, when buds are extending from the crown, and after renovation, when plants are beginning to grow back after mowing.
  
• Beneficial mites and thrips will feed on cyclamen mites. Excessive use of pesticides, especially pyrethroid insecticides, which are highly toxic to beneficial mites, can disrupt beneficial insect populations and lead to outbreaks of cyclamen mite.
  
• Purchase healthy plants grown in an accredited program.
  
• Avoid working in infested fields and then moving to newer, or uninfested plantings.