Sphaeropsis sapinea and water stress in a red pine plantation in central Wisconsin

• Published in: Phytopathology Vol. 87; no. 4; pp. 429 - 434
• Main Authors: Blodgett, J.T. (University of Wisconsin, Madison.), Kruger, E.L, Stanosz, G.R
• Format: Journal Article Conference Proceeding
• Language: English
• Published: St. Paul, MN American Phytopathological Society 01.04.1997
• Subjects: AGENT PATHOGENE; Biological and medical sciences; COMPETICION VEGETAL; COMPETITION VEGETALE; CRECIMIENTO; CROISSANCE; ENFERMEDADES FUNGOSAS; ENSAYO; ESTRES DE SEQUIA; ETAPAS DE DESARROLLO; FEUILLE; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; HOJAS; LLUVIA; MALADIE FONGIQUE; ORGANISMOS PATOGENOS; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; PATHOTYPE; PATOGENICIDAD; PATOTIPOS; Phytopathology. Animal pests. Plant and forest protection; PINUS; PINUS BANKSIANA; PINUS RESINOSA; PLUIE; POUVOIR PATHOGENE; RELACIONES HUESPED PARASITO; RELACIONES PLANTA AGUA; RELATION HOTE PARASITE; RELATION PLANTE EAU; SECHERESSE; SEQUIA; SINTOMAS; SPHAEROPSIS; STADE DE DEVELOPPEMENT; STRESS DU A LA SECHERESSE; SYMPTOME; TESTAGE; VARIACION ESTACIONAL; VARIACION GENETICA; VARIATION GENETIQUE; VARIATION SAISONNIERE; VEGETACION; VEGETATION; WISCONSIN; United States; North America; Wisconsin; America; Disease development; Atmospheric condition; Pinus resinosa; Plant pathogen; Environmental factor; Strain specificity; Vegetation effect; Water stress; Field experiment; Herbicide; Fungi; Artificial forest stand; Softwood forest tree; Gymnospermae; Chemical control; Coniferales; Spermatophyta; Plant cover; Fungi Imperfecti; Drought; Thallophyta
• ISSN: 0031-949X; 1943-7684
• DOI: 10.1094/PHYTO.1997.87.4.429

A study was conducted to determine the effects of water stress resulting from competing vegetation on disease development of Sphaeropsis sapinea in red pine plantations. A 9-year-old plantation was selected in 1992 and experiments were conducted for three consecutive years. Four treatments were assigned at random to individual trees: no treatment, herbicide to kill surrounding weeds, supplemental water, and both herbicide and supplemental water. Two isolates of each S. sapinea morphotype (A and B) were used to inoculate wounded lateral shoots. Disease development was measured as the maximum distance below the inoculation site at which necrotic needles were observed. Nonwatered trees with competing vegetation (nontreated condition) had significantly lower predawn needle water potentials (more water stress) and more severe disease development than trees that received the herbicide, water, or combined herbicide and water treatments. The most severe disease occurred in the driest year and the least in the wettest year. Competing vegetation indirectly affected disease development by inducing water stress, even in relatively moist years, on trees previously considered well established. Isolates of morphotype A were more aggressive than isolates of morphotype B. Conclusions from this research have implications for sustainable management of the region's conifer forests