Submitted to: Pecan Grower
Publication Type: Trade Journal
Publication Acceptance Date: 6/25/2009
Publication Date: 7/15/2009
Citation: Wood, B.W. 2009. What is the relationship between mineral nutrition and disease management?. Pecan Grower. 21(1):26-29.
Interpretive Summary: There is great need to reduce the cost of disease control in commercial pecan orchards and in yard trees. Research and anecdotal evidence indicates that improving tree nutritional physiology can reduce the incidence and severity of certain diseases of pecan. Improved nutrient management offers an important means of reducing the damage and costs of certain pecan diseases.
Technical Abstract: Pecan disease management potentially influences efficient use of fertilizer and other expensive orchard inputs. Optimization of tree nutrient element physiology is key to the expression of a cultivar’s full potential to express resistance to disease. This is especially important in cultivars possessing a degree of disease resistance to begin with. There appears to be great potential for the mediation of certain diseases through optimization of orchard fertilization management. While it is not likely possible to prevent the incidence of disease via nutrition management, the severity of disease can potentially be reduced. Orchard managers should note that most pecan trees evolved in moist, well-drained, high organic, and acidic soil environments. When trees grow in relatively alien-like soils with little or no organic matter, and with a deficiency or imbalance of nutrient elements, and with an unnatural soil microbial population, then their ability to fully express their innate disease resistance potential can be limited. This limitation is exasperated when tree growth is maximized via heavy applications of nitrogen and water in order to maximize nutmeat yield. The associated dilution effect of most nutrients, due to excessive growth, can easily trigger transitory nutrient deficiencies that influence disease resistance. The closer orchard soils are managed to mimic the soils of pecan’s native habitat, the more likely that the incidence and severity of disease is reduced, and more easily controlled by fungicides when applications are necessary. The critical developmental windows for ensuring optimal impact of nutrients key to the minimization of disease problems is typically during rapid growth phases, such as canopy expansion and rapid fruit expansion. Thus, it is during these phases that attention to nutrient element management is most likely to influence disease management of many diseases affecting foliage and fruit (e.g., pecan scab disease).