Can you explain why delaying apple harvest is sometimes beneficial?


In your article on bitter pit by  Andris et al., it is stated that if the ethylene ripening test done 2 weeks before harvest is positive then ‘’delay the harvest for as long as possible.’’  Could you please explain why the delay is beneficial and the physiology behind this?  Also how long can you hold the fruit on the tree before quality becomes an issue?  (F.G.)


The logic for the delayed harvest is that less mature fruit (earlier harvested) are generally more susceptible to bitter pit.  However, in recent years we have not always seen such a strong harvest effect, at least in California but it is generally accepted that earlier harvested fruit are more susceptible.  You would not want to delay harvest so far that the fruit were too mature for their intended use.  This would depend on the cultivar and whether you were planning to sell or utilize quickly or store for many months.  The produce fact sheets on our website give some information about the proper harvest maturity for some apple cultivars.