VIEW ARTICLE

Ecology and Epidemiology

Growth of Verticillium dahliae on Sap from Five Maple Species. F. J. Regulski, Jr., Department of Plant Pathology, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick 08903, Present address: University of Florida, Agricultural Research Center, Rte. 4, Box 63, Monticello 32344; J. L. Peterson, Department of Plant Pathology, Cook College, New Jersey Agricultural Experiment Station, Rutgers University, New Brunswick 08903. Phytopathology 73:115-118. Accepted for publication 12 July 1982. Copyright 1983 The American Phytopathological Society. DOI: 10.1094/Phyto-73-115.

To determine the ability of the wilt disease fungus, Verticillium dahliae, to grow on maple tree sap, sap samples were taken at the dormant, bud-swell, bud-break, and full-leaf physiological stages of the tree and were used as growth media for the fungus. Naturally seeded Acer negundo, A. saccharum, A. rubrum, A. platanoides, and A. saccharinum were used. Verticillium growth on Czapek-Dox broth at various temperatures indicated that soil and tree temperatures occurring at the dormant and bud-swell stages were unfavorable and temperatures occurring at the bud-break and full-leaf stages were favorable for fungal growth and sporulation. Red and silver maple sap were the most favorable media when taken at stages when temperatures favored rapid fungal growth and sporulation. Fungal growth and sporulation on Norway and sugar maple sap reached a peak at the bud-break stage, but as temperature became more favorable, at the full-leaf stage, the sap supported less growth and sporulation. Boxelder sap was the best medium at the bud-swell stage, when the temperature was unfavorable for fungal growth, but as the temperature became more favorable, boxelder sap became a poor medium for fungal growth and conidial and microsclerotial production. This may explain the resistance of boxelder to the wilt disease. Verticillium growth in maple may be influenced by the nutrient level or the possible presence of inhibitors in the sap at various tree growth stages.