VIEW ARTICLE

Disease Control and Pest Management

Distribution and Retention of Thiabendazole Hypophosphite and Carbendazim Phosphate Injected into Mature American Elms. M. A. Stennes, Former research assistant, Department of Plant Pathology, University of Minnesota, St. Paul 55108; D. W. French, Professor, Department of Plant Pathology, University of Minnesota, St. Paul 55108. Phytopathology 77:707-712. Accepted for publication 14 October 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-707.

When exposed root flares were injected with solutions of thiabendazole hypophosphite and carbendazim phosphate, the fungicides became completely and evenly distributed in all of the outer sapwood in the crown of mature American elms (Ulmus americana) provided the dose was adequate. Carbendazim phosphate applied at 0.98 and 1.95 g a.i. per centimeter of trunk diameter and thiabendazole hypophosphite applied at 1.86, 3.72, 5.59, and 8.94 g a.i. per centimeter of diameter apparently protected mature elms from Dutch elm disease during the year of injection. Only thiabendazole hypophosphite applied at 5.59 and 8.94 g/cm of diameter was detected by bioassay in the newest radial wood during the second and third growing seasons after injection. At a rate of 5.59 g/cm, thiabendazole hypophosphite applied at a concentration of 3.0 g/L and volume rate of 1.86 L/cm of diameter apparently maximized distribution and retention of the fungicide.