The Role of Nutrition in Crop Resistance and Tolerance to Diseases

Abstract

Nutrients are part of the "environment" for plant and microbial growth and, although frequently unrecognized, always have been an important factor in disease control. All the essential nutrients are reported to influence the incidence or severity of some disease (see Table 7.1); however, no single nutrient controls all diseases or favors disease control for any one group of plants (Graham, 1983; Engelhard, 1989; Huber, 1991). A particular element may decrease severity of some diseases, but increase others (see Figure 7.1), and have an opposite effect in a different environment. The effects of N (nitrogen), P (phosphorus), and K (potassium) on disease are reported more frequently than the effects of minor nutrients because of the limited availability of the macronutrients in many soils relative to the large quantity required for optimum plant growth. Nevertheless, it is through an understanding of the disease interactions with each specific nutrient that the roles of the plant, pathogen, and environment can be effectively modified for improved disease control.

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