A Large-Scale Dilemma:
Drawing shows a shrinking female armored scale laying eggs. Waxy covers of each of the 3-instars are pushed above the other. Crawlers emerge from the female cover through the one-way flap. (Drawing Credit: John Davidson, Univ. of MD)
Undoubtedly many arborists, landscapers, nurserymen, and golf course superintendents would agree that effectively controlling scale insects is one of the more frustrating pest management challenges encountered. Of the half-dozen major families of scale insects common in the urban landscape, the armored scales are the most troublesome. With their protective waxy covering, armored scales are considerably less susceptible to various insecticide spray treatments.
Reddish colored crawlers of Pine Needle Scales emerging out from under female waxy covers. (Photo Credit: Ohio State Coop. Ext.)
Historically, many pesticide spray applicators fail to achieve satisfactory controls because they do not have the time or inclination to apply sprays during the scale crawler emergence periods. To complicate matters, the crawler periods for the various armored scale species are quite variable. Furthermore, the improper timing of long residual pyrethroid insecticides can virtually eliminate important parasitoid bio-control activity and hence, often encourage scale infestations. The intention of this blog is to stress the importance of properly timed treatments to achieve better management of scale insects. This is especially true when attempting to control armored scales.
Despite the complications stated above, fortunately some relatively newer insecticides have given improved abilities for scale controls. These newer materials & the life cycles of 5-armored scale species will be covered in this blog. The scales covered include: 1-Euonymus scale; 2-Cryptomeria scale; 3-Japanese maple scale; 4-White Prunicola scale; & 5-Juniper scale.
