Japanese Maple Scale Activity and Management in Field Nursery Stock

Japanese maple scale is a generalist armored scale with a wide host range including many high value deciduous trees and shrubs. It has been reported on plants in at least 28 families 50 genera. As an armored scale, the purple, soft-bodied insects are shielded from many predators and pesticides by a white, waxy covering that appears similar to an oyster shell. High infestation levels can lead to, plant stunting, branch dieback and plant death. Old scale covers from dead scales can remain attached to the bark of trees for an extended period of time and the presence of scale covers can result in rejection of nursery product regardless of wheher the insects are alive or dead. The waxy armor secreted by armored scales combined with their feeding habit and overlapping generations, makes Japanese maple scale difficult to manage. We investigated the seasonal activity of Japanese maple scale in middle Tennessee and several chemical products for management of JMS in field nursery production.