Sunday, April 5, 2009

Landscape - Scale Insects: European Fruit Lecanium

This is the third in a series on scale insects in the landscape. It is a description of the European Fruit Lecanium. Information is from the University of Maryland.

European Fruit Lecanium (Parthenolecanium corni), Family Coccidae

Plants Damaged: This soft scale occurs on many shade tree species including hawthorn, red maple, pyracantha, and other plants in the rose family. The European fruit lecanium is a common soft scale insect pest of shade trees and other woody ornamental plants in Maryland (and Delaware). This species feeds on a wide range of host plants and is considered polyphagous. Populations of this pest build up quickly so monitoring for this pest on potential host plants is important.

Damage Symptoms: Feeding damage may cause curled, chlorotic foliage that may drop prematurely. Smaller infested branches are weakened due to feeding injury or in some cases may be killed. Also, when this soft scale species is feeding on leaves and twigs, a large quantity of honeydew is secreted.

Life Cycle: The 2nd instar females overwinter on the branches. The females will start to swell-up in May and crawlers emerge in late May to early June. Nymphs move out onto foliage where they feed in summer and migrate back to the stems and trunk to overwinter.

Monitoring: Look for sooty mold growing on the honeydew excreted on the foliage and branches. Inspect branches using a 10 -16X magnifier for crawlers

Control: Distance and 1% horticultural oil applied when crawlers are active gives good control. Another option is soil applications of imidacloprid or dinotefuran as a soil drench.

European Fruit Lecanium. Photo by Raymond Gill, California Department of Food and Agriculture,

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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