Trimble, F.M. 1929 Scale insects injurious in Pennsylvania.. Bulletin of the Pennsylvania Department of Agriculture 12: 1-21.

Notes: Review of Asterolecanium variolosum, Gossyparia spuria, Phenacoccus acericola, Pseudococcus sp., Pulvinaria acericola, Eucalymnatus tessellatus, Coccus sp., Toumeyella liriodendri, Lecanium nigrofasciatum, Lecanium prunastri, Saissetia hemisphaerica, Chionaspis americana, C. euonymi, C. furfura, C. pinifoliae, Diaspis boisduvalli, D. carueli, Aulacaspis rosae, Aspidiotus hederae, A. perniciosus, A. rapax, Chrysomphalus aonidum, C. dictyospermi and Lepidosaphes ulmi; common names; brief field descriptions; hosts; chemical or mechanical control techniques recommended; photographs.