Pitch Canker Caused by Fusarium circinatum Identified on Spruce Pine in Alabama.

A dieback associated with resinous branch and main stem cankers was observed on two spruce pine (Pinus glabra Walt.) trees in Lee County, Alabama in July 2002. Xylem tissues beneath the cankers were resinsoaked as is characteristic of pitch canker on other southern pine species. Surface-sterilized stem pieces from the canker margins were transferred to acidified potato dextrose agar and incubated at 22°C for 5 days. Mycelium from these plates was transferred to low nutrient agar where polyphialides and sterile, coiled hyphae characteristic of F. circinatum Nirenberg & O'Donnell (= F. subglutinans Wollenweb. & Reinking) developed (1). Ten 5-month-old loblolly (Pinus taeda L.) and spruce pine seedlings inoculated with a spruce pine isolate of F. circinatum (NRL 32523, deposited in the USDA, ARS Culture Collection in Peoria, IL) developed cankers and produced resin along seedling stems. Isolates recovered from the symptomatic seedlings were again identified as F. circinatum. Spruce pine, while seldom abundant, is found scattered among hardwoods along riparian zones through the southern Gulf States to South Carolina. Although pitch canker was first described on Virginia pine (P. virginiana Mill.) in 1946 and has since been reported in California, South Africa, Spain, and Chile on 25 other pine species (2), to our knowledge, this is the first report of F. circinatum causing pitch canker on spruce pine. References: (1) H. I. Nirenberg and K. O'Donnell. Mycologia 90:434, 1998. (2) A. J. Storer et al. J. For. 95:21, 1997.