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Pierluigi (Enrico) Bonello, The Ohio State University, Department of Plant Pathology; James T. Blodgett, Daniel A. Herms, |
Little is known about how soil nutrients affect pine diseases. In a survey of red pine (Pinus resinosa) and jack pine (P. banksiana), tree mortality attributed to Sphaeropsis sapinea was as high as 30% for red pine and 51% for jack pine (Nicholls and Ostry, 1990). Such high mortality levels were attributed to, among other factors, poor site conditions.
However, in another field survey of red pines, mortality was correlated with paper-mill waste application and linked to higher foliar nitrogen in the treated stands (Stanosz and Trobaugh, 1996). Van Dijk etal. (1992) also correlated increased disease development by S. sapinea with high soil nutrient concentrations.
Although losses to S. sapinea have been associated with nutrient conditions, results are based on field observations and field surveys. These observations and surveys do not provide information on the quantitative effects of nutrition on disease development and cannot separate the effects of nutrients from many other possible environmental factors. Thus, basic studies must be performed. Preliminary data recently generated in our program have begun to answer some of these questions.