Up to the present time little attention has been given to the diagnosis of nutritional disorders in tamarillos. Experience with other crops such as kiwifruit has shown that visual symptoms can play an important part in diagnosing nutrient deficiencies and toxicities in the field. Clearly recognisable leaf symptoms associated with a specific disorder usually appear only after metabolic functions in the plant have been seriously disrupted and losses of yield already sustained. Thus, the presence of visible leaf symptoms usually indicates that a serious problem exists. This article describes visual symptoms of nutrient disorders in tamarillos so that they can be distinguished from non-nutritional causes.
Accurate diagnosis is important if nutrient disorders are to be dealt with effectively.
Thus, confirmation of any visual diagnosis needs to be supported with evidence from plant and soil analysis. Although critical leaf concentrations for tamarillos have yet to be determined, some indication of the concentration of individual elements required in the leaf can be gauged from the results in Table 3 and from the results given in this article of concentrations found in leaves of plants showing clearly recognisable symptoms of deficiency or toxicity. Samples may be taken any time during the growing season and compared to optimum ranges. For monitoring, leaf samples should be taken at the same each year to compare. If nutrient disorders are suspected, leaf samples may be taken as soon as the problem is noted.