Wednesday, April 8, 2009

Landscape - Scale Insects: Fletcher Scale

This is the sixth in a series on scale insects in the landscape. This post is on the Fletcher Scale. Information is from the University of Maryland.

Fletcher Scale (Parthenolecanium fletcheri (Cockerell)), Family Coccidae

Plants Damaged: Arborvitae (Thuja species), and yews (Taxus) are the two plants this soft scale is commonly found on in Maryland. It has been reported on pachysandra and juniper.

Damage Symptoms: Besides causing yellowing of foliage this scale will produce large amounts of honeydew in spring on which sooty mold grows.

Life Cycle: This scale overwinters as 2nd instar females that mature in May. The overwintering females are oval shaped and flattened in profile. In May the females will swell and become distended. The eggs will hatch into crawlers sometime in June- about the time when catalpa trees bloom.

Monitoring: Examine stems of arborvitae and yews in winter looking for the oval shaped overwintering females. In May and June, look for honeydew and sooty mold.

Control: Distance applied when crawlers appear or a soil injection of imidacloprid (Merit) or dinotefuran (Safari).

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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