Monday, April 27, 2009

Landscape - Scale Insects: Holly Pit Scale

This is the 19th in a series on scale insects in the landscape. This post is on the Holly Pit Scale. Information is from the University of Maryland.

Holly Pit Scale (Aterolecanium puteanum Russell), Family Asterolecandidae

Plants Damaged: American holly, Burford holly, and Japanese holly. Most of the infestations have been found on holly growing on the Eastern shore of Maryland.

Damage Symptoms: Pitting and distortion of woody tissue on branches and trunk of the tree. Heavy infestations cause dieback of the plant.

Life Cycle: Mature females overwinter in a pit. The pit is caused by the feeding damage to the plant tissue. Crawlers emerge over a long period of time during the summer. Once nymphs have settled on a place on the plant they do not move.

Monitoring: Examine twigs and trunk of tree for pit-like depressions with a scale insect in the middle of the pit.

Control: Horticultural oil or Distance and oil applied when crawlers are present.

Photo by Mike Raupp, University of Maryland

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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