Tomatoes need to be free of the different disorders and rots in order to meet market requirements. The extent of these varies according to environmental conditions, varietal susceptibility and crop nutrition.
Crop Nutrition and Wine Grape Health
Nitrogen is a component of proteins and metabolic compounds involved in disease defense. Disease control through nitrogen management is generally indirect, but it is an important mean of increasing wine grape production efficiency.
It has been widely reported that balanced and adequate supply of phosphorus reduces stress, improves physiological resistance, and decreases risk of diseases.
Potassium alone or in combination with nitrogen, phosphorus and other nutrients can minimize the severity of diseases, because potassium is involved in several metabolic processes as regulator of several physiological pathways.
Calcium is a constituent of the cell wall and middle lamella of plant cell, thus the direct relation between calcium ions and cell wall partially explains resistance to invasion of pathogens. It plays a critical role in lignification and wood maturity, which gives the wine grape a greater tolerance to frost. Calcium is also very important in providing an elasticity of cell walls, reducing the impact of disease and minimizing end of season cracking and splitting.
Magnesium supports healthy growth and development of crop. It is a component of structural tissues and participates in physiological functions and biochemical processes. Application of magnesium fertilizer resulted in decrease of bunch stem necrosis.
Sulphur and sulphur compounds affect disease incidence and severity directly as biocides and indirectly by enhancing mechanisms of crop resistance. Supply of insufficient amount of micro nutrients hinder health of crop because micronutrients are involved in several metabolic activities that support defence and tolerance mechanisms of crop against diseases.
Boron involvement in lignification and phenol metabolism indicate its benefit in crop defence mechanism against disease.
Copper is a cofactor of enzyme systems required in stimulation of crop defence mechanisms against diseases.
Iron is involved in metabolic activities important during respiration, DNA synthesis and photosynthesis that all these processes play major roles in disease defence systems of crop.
Manganese is involved in the metabolism of carbohydrate and nitrate, thus it can provide opportunity for direct and indirect effects on defence mechanism of crop.
Molybdenum deficiency limits growth of crop because it is involved in synthesis or regulation of hormones.
Zinc plays an essential role in the processes of cell multiplication, and can therefore limit healthy growth of the crop.