Wednesday, April 15, 2009

Landscape - Scale Insects: Cryptomeria Scale

This is the 13th in a series on scale insects in the landscape. This post is on the Cryptomeria Scale. Information is from the University of Maryland.

Cryptomeria Scale (Aspidiotus cryptomeriae Kuwana), Family Diaspididae

Plants Damaged: This scale is found on many conifer species including fir, Cedrus, Chamaecyparis, rarely this scale is found on Cryptomeria, pine, spruce, Taxus and hemlock.

Damage Symptoms: As the scale draws out sap from the needles it causes a yellowing spotting of the foliage. Heavy infested plants are chlorotic. Dieback occurs when populations are high.

Life Cycle: This scale overwinters as second instar females. Adults occur in spring in March and April. Females lay eggs in June with crawlers appearing in June through early July. There are two generations per year. Adults of the second generation are present in July and crawlers are present in late August through September. Immatures overwinter on the needles.

Monitoring: Look for chlorotic foliage with yellow spotting or banding on the needles. Look for overwintering scale on the needles.

Control: A mixture of 1% horticultural oil and Distance does a great job of controlling this scale. Dinotefuran (Safari) applied as a soil drench also works well.

Information from "Scales Commonly Encountered in Maryland Landscapes and Nurseries" by Stanton Gill, Extension Specialist in IPM for Nurseries and Greenhouses,and Suzanne Klick and Shannon Wadkins, Technicians, Central Maryland Research and Education Center University of Maryland Cooperative Extension.

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