The Effects of Thiabendazole on Fusarium subglutinans, the Causal Agent of Pitch Canker of Loblolly Pine. G. B. Runion, Graduate Research Assistant, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616. R. I. Bruck, Associate Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616. Plant Dis. 72:297-300. Accepted for publication 30 October 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0297.

Effects of thiabendazole on growth of Fusarium subglutinans in culture and on pitch canker symptom expression on artificially inoculated loblolly pine seedlings were studied. The efficacy and duration of efficacy of various concentrations of thiabendazole on natural infection of loblolly pine seedlings in the field were also investigated. Growth of the fungus in vitro was suppressed at 0.1 ?g a.i./ml of thiabendazole and completely inhibited at 1.0 ?g a.i./ml. Thiabendazole treatment prevented symptom expression and recovery of F. subglutinans from artificially inoculated loblolly pine seedlings under greenhouse conditions. A negative linear relationship existed between natural infection of loblolly pine seedlings in the field and thiabendazole concentration, with 21.3 g a.i./L resulting in the lowest pitch canker incidence. Thiabendazole at 14.2 g a.i./L controlled pitch canker for 9 wk; higher concentrations were necessary for extended control, however.