A Review of Chemical Treatments to Improve Germination of Longleaf Pine Seeds

Abstract

Nursery managers can improve germination of longleaf pine (Pinus palustris P. Mill. [Pinaceae]) seeds and seedling establishment by reducing seedborne pathogenic fungi with appropriate sterilants and fungicides. We have tested many chemicals, but hydrogen peroxide, thiophanate methyl, and thiram seem to provide the best results in reducing the large populations of microorganisms carried on the large, thin, and fibrous seed coats. Our evaluations of longleaf seeds indicate that Fusarium spp. are major seedborne pathogens that cause mortality to seeds and newly germinated seedlings. Seeds of other southern pines have denser coats and are less adversely affected by the presence of seedborne pathogens. The increased demand for longleaf pine seeds in the last few years makes reducing this contamination an important consideration by seed dealers and nursery managers.