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Horticulture/Quadraspidiotus perniciosus
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
San Jose Scale Quadraspidiotus perniciosus Hemiptera Simple Nymphs Crawler
San Jose scale is a pest of both orchards and ornamental plants. The insect is originally from China, but introduced in North America in the late 1900s as an invasive species.
Description
Circular hard scales, generally in great numbers. Adult males are winged, females remain under the scale.
Symptoms and Signs
Severe infestations can kill the host plant if not treated.
Host plants
../Asclepias/
../Buxus/
../Celtis/
../Cornus/
../Crataegus/
../Cydonia/
../Fagus/
../Gleditsia/
../Juglans/
../Ligustrum/
../Lonicera/
../Maclura/
../Malus/
../Morus/ (Mulberry)
../Pachysandra/
../Photinia/
../Prunus/
../Ribes/
../Robinia/
../Rosa/
../Rhamnus/
../Sassafras/
../Sorbus/
../Syringa/ (Lilac)
../Thuja/ (Arborvitae)
../Tilia/
../Viburnum/
Control
Electrical tape (sticky side out) around a branch can detect the presence of crawlers. Prune out infested branches ../Horticultural Oil/ (dormant spray), ../Neem Oil/ Wasps including ../Encarsia perniciosi/ and ../Aphytis/ spp.
References
Virginia Tech
West Virginia University
Ohio State University