By Dr. David L. Clement, University of Maryland Extension Specialist, Home and Garden Information Center. Revised 4/2020.
Johnson, W.T. and H.H. Lyon. 1991. Insects That Feed on Trees and Shrubs, 2nd Ed. Ithaca, NY: Comstock Publishing Associates, Cornell University Press. 560 pp.
Pirone, P.P. 1978. Diseases & Pests of Ornamental Plants, 5th Ed. New York: John Wiley & Sons. 566 pp.
Sinclair, W.A. H.H. Lyon, and W.T. Johnson. 1987. Diseases of Trees and Shrubs. Ithaca, N.Y.: Comstock Publishing Associates, Cornell University Press. 574 pp.