Fletcher Scale Diagnostic Guide
Yew fletcher scales weaken plants by sucking the sap out of the leaves and twigs. This loss of plant fluid causes yellowing of the needles and early needle drop. They also create large amounts of honeydew, a sugary, sticky material that results in a crusty black sooty mold on foliage and branches.
Trees and Shrubs at Risk
Yew is preferred, but arborvitae and juniper are also susceptible.
Signs of Damage
- Fletcher scales produce large amounts of honeydew (a sugary, sticky material) that results in a crusty, black sooty mold on foliage and branches. Ants, bees, and wasps may be attracted to the honeydew.
- Severe infestations can weaken plants causing the needles to turn yellow and drop early.
- Heavily infested trees may display dieback of branches and twigs.
- Crawlers are oval, flat, and yellowish.
- Adult females are yellowish brown, dome-shaped, about 2-4mm in diameter, and found on small twigs.
- After overwintering, the yew fletcher scales begin rapidly developing in the spring.
- Females begin laying 500-600 eggs in late spring, which hatch into crawlers between May and early July and remain on the plant for the remainder of the season.
- Crawlers are most active from June to July.
- There is one generation per year.
Spring soil applications of Xytect™ may provide acceptable levels of control if applied early enough in the growing season. Transtect™ can be applied to the soil in early spring to kill current year crawlers. When an infestation reaches an undesirable level, the primary goal is to control the crawler stage of the insect’s life cycle using foliar sprays of Up Star Gold™, Xytect™, or Transtect™. Be sure the sprays penetrate the entire plant canopy. Crawlers are most active in the early summer, and are very susceptible to insecticide control. Once settled on leaves or twigs, they secrete a waxy covering that provides protection, so timing of sprays is important.
Use foliar sprays for immediate activity against crawlers. Manage overwintering females on the twigs with dormant sprays. Properly timed soil applications of Xytect™ or Transtect™ will work extremely well for most soft scales.
A Diagnostic Guide is designed to help you identify a pest issue and management solutions. Always refer to product label for all rates and approved uses. Some images courtesy forestryimages.org. Use of the images does not imply endorsement of treatments by forestryimages.org