VIEW ARTICLE

Disease Detection and Losses

Branch Dieback and Cone and Seed Infection Caused by Fusarium moniliforme var. subglutinans in a Loblolly Pine Seed Orchard in South Carolina. Jane Barrows- Broaddus, Research plant pathologist, USDA Forest Service, Southeastern Forest Experiment Station, Forestry Sciences Laboratory, Carlton Street, Athens, GA 30602; L. D. Dwinell, research plant pathologist, USDA Forest Service, Southeastern Forest Experiment Station, Forestry Sciences Laboratory, Carlton Street, Athens, GA 30602. Phytopathology 75:1104-1108. Accepted for publication 7 May 1985. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1985. DOI: 10.1094/Phyto-75-1104.

Incidence of shoot dieback in a loblolly pine seed orchard varied by clone. All but the most susceptible clones recovered from the dieback. Fusarium moniliforme var. subglutinans was isolated from branches, conelets, mature cones, and seeds. Pathogenicity tests on loblolly and Virginia pine seedlings indicated that the same pathotype of F. moniliforme var. subglutinans causing shoot dieback also caused deterioration of pine reproductive structures. The pattern of fungus isolation and the histological data indicated that outbreaks of shoot dieback and conelet deterioration could occur independently. A comparison of radiographs showed only slight differences in shape between infected and noninfected seeds. Fungus-damaged seeds occurred only in cones atypical in shape or having necrotic areas on the scales.