Steam-End Rind Breakdown (SERB) on Citrus fruits

Recently, a deficiency has been found in a few citrus fruit inspections which could not be directly classified (see picture). This is the so-called Stem-End Rind Breakdown (SERB). This results in wilting around the stem base and a brownish discoloration. The skin sinks in somewhat at this point. This makes the fruit more susceptible to stem-end rot and other pathogens. There are various causes for this deficiency. In addition to imbalances in the nutrients N and K in the field, dry conditions between harvest and treatment with waxes can also contribute to the development of the deficiency.