SUMMARY.The spores of rot forming fungi on the surface of the apple and in the lenticel cavities have been studied as regards their distribution and number.The natural modes of entry of apple rot fungi have been described and the relative frequency of their occurrence assessed.The factors controlling lenticel invasion in storage have been analysed by a new experimental technique.The literature dealing with lenticel spotting of apples has been reviewed; the cause of spotting has been distinguished as functional rather than fungal and the general name “Lenticel Spot” has been proposed for the dise