Can fertilization with paper mill waste sludge threaten forest health and productivity? Shoot blight and canker found in treated red pine stands.
During 1993 progressive, severe shoot blight and canker disease in crowns of mature, merchantable red pines (Pinus resinosa) in central Wisconsin was investigated. The percentage of branch tips colonized by the pathogenic fungus Sphaeropsis sapinea (Diplodia pinea) was quantified in 5 plantations. Soil and foliage samples were also collected for nutrient analyses. Sample stands included three previously treated with paper mill sludge and two untreated stands. Shoot colonization by D. pinea was more frequent in treated stands than in untreated stands where it was rare. Foliar nitrogen concentrations, which have been associated with severe D. pinea shoot blight and canker, were higher in treated than in untreated stands.