Citrus rind pitting is a rind disorder in grapefruit and oranges. The
symptoms occur post-harvest and appear as sunken spots on the rind about 0.3 to
m0.6cm in diameter. The disorder is responsible for heavy crop losses. In some
seasons large amounts of export fruit are rejected at the ports for rind
pitting.
Research conducted by the Post-harvest unit of the ARC-ITSC have clearly
shown that over-fertilizing with nitrogen is the most common cause of rind
pitting in grapefruit on certain farms in the Mpumalanga area. A subsequent
survey further suggested that overfertilizing with nitrogen is a major cause of
deep rind pitting in Midknight Oranges. Queries from various other areas
regarding this aspect have further served to enforce our opinion regarding this
aspect.
In spite of the above, considerable superficial rind pitting still occurs
each year in correctly over-fertilized Valencia oranges, especially, in the
Benny Valencia variety. Ironically, surveys conducted strongly suggested that
nitrogen deficiency during the second half of the growing season contributes
towards the problem, particularly in sandy soils.
In this study, we attempt
to reduce the incidence of rind pitting in Benny Valencia oranges by applying
small rates of nitrogen towards the end of the season.
