Effects of Thiabendazole-DMSO Treatment of Longleaf Pine Seed Contaminated with Fusarium subglutinans on Germination and Seedling Survival. G. B. Runion, Former 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. 72:872-874. Accepted for publication 12 May 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0872.

A thiabendazole-dimethyl sulfoxide soak increased in vitro germination of longleaf pine seed known to be contaminated with the pitch canker fungus, Fusarium subglutinans. Thiabendazole also resulted in lower percentages of seed and seedlings contaminated with the fungus. Thiabendazole was applied as Mertect 340F at concentrations of 423, 1,268, 2,114, 2,537, 3,382, or 4,228 ?g a.i./ml and as Arbotect 20S at concentrations of 266, 798, 1,330, 1,596, 2,128, or 2,660 ?g a.i./ml. Fungicides were suspended in 10% dimethyl sulfoxide to enhance efficacy. The 2,660 and 3,382 ?g a.i./ml concentrations resulted in the highest germination rates for the Arbotect and Mertect treatments, respectively, but were not significantly different from most concentrations tested. All treatments reduced the recovery of F. subglutinans from seed that did not germinate and from seedlings compared with controls. The higher concentrations tended to be most effective. Arbotect was the more effective of the two formulations tested. The 2,660 ?g a.i./ml treatment resulted in the highest germination rate and the lowest recovery of F. subglutinans from seedlings.