Excess nitrogen increases disease and storage problems in mangoes

A study published in Scientia Horticulturae indicates that adjusting nitrogen inputs can help reduce diseases, pests and physiological disorders in mangoes, while also improving fruit quality during postharvest storage.

The research examined the effects of different nitrogen rates, sources and application strategies over three growing seasons, from 2022 to 2024, in a commercial orchard of ‘Shelly’ mangoes. The results show that high nitrogen inputs increased tree susceptibility to certain diseases and encouraged the development of postharvest disorders.

Higher nitrogen inputs increase disease incidence

Increasing nitrogen fertilization was consistently associated with a higher incidence and severity of powdery mildew, caused by Pseudoidium anacardii, and branch dieback, mainly associated with Neofusicoccum parvum.

The effects were also observed after harvest. High nitrogen rates increased fruit losses caused by decay, including stem-end rot associated with Botryosphaeria and side rot mainly caused by Alternaria alternata. The lowest incidence of these problems was recorded at an annual application rate of 50 kg of nitrogen per hectare.

Another key finding was the increase in jelly seed, a physiological disorder characterised by changes in the internal flesh. At the highest rate, 200 kg of nitrogen per hectare per year, its incidence reached up to 53%, whereas treatments with lower nitrogen inputs showed much more limited development.

Nitrogen rate matters more than its source

The trial compared seven fertilization regimes, with applications of 0, 50, 120 and 200 kg of nitrogen per hectare per year, alongside different nitrogen forms and application methods. According to the results, the total amount applied had a clearer influence than the nitrogen source or application timing, whose effects were smaller or inconsistent.

Pest pressure was generally low during the study. Nevertheless, the proportion of fruit free from visible scale insects was highest in plots that received no nitrogen, a result that should be interpreted in the context of the specific trial conditions.

Balancing yield and postharvest quality

Overall, the researchers conclude that moderate nitrogen fertilization can balance crop production, plant health and fruit quality. Complementary agronomic results from the same orchard identified 50 kg of nitrogen per hectare per year as the optimal rate for maximising yield.

The study highlights the importance of matching fertilizer applications to crop requirements. Increasing nutrient inputs does not necessarily guarantee a better harvest and may increase phytosanitary problems and losses during storage.

Source

Yelin, M. D., Rotbart, N., Nevo, E., Maurer, D., Feygenberg, O., Shaltiel Harpaz, L., Sofer Arad, C., & Alkan, N. (2026). Optimal nitrogen fertilization reduces disease and pest susceptibility and postharvest disorders in mango. Scientia Horticulturae. https://doi.org/10.1016/j.scienta.2026.115220