Sprays of gibberellins (e.g. Regulex, Novagib) can improve the skin finish of varieties such as Cox at harvest time. GA4+7 is approved for use in the UK and trials have demonstrated that small but significant increases in % Class 1 fruit can be achieved.
As fruitlets can be sensitive to russetting over a long period, a programme of sprays is regarded as better practice than just one or two applications.
On varieties such as Cox and Discovery apply sprays of GA4+7 (e.g. Regulex or Novagib) at label recommendations (4 times at 5-10 ppm, at 10 day intervals commencing at first open flower) so as to improve skin finish at the time of harvest.