Author Affiliations +
Dennis vanEngelsdorp,1 Leo R. Donovall1
1(DVE) Department of Entomology, The Pennsylvania State University, University Park, PA 16802, U.S.A. and Pennsylvania Department of Agriculture, Bureau of Plant Industry—Apiary Section, 2301 N. Cameron St., Harrisburg, PA 17110, U.S.A. (e-mail: (LRD)