Superficial scald is still one of the most important postharvest physiological disorders in apples. Commercial control of this disorder has been accomplished by selecting resistant cultivars, treating fruit with DPA and ethoxyquin, using oil-soaked fruit wraps and storing the fruit under low O2. However, the causal reason for scald development is still a mystery. Research has indicated that the scald-promoting factor or inducing compound may be formed or accumulated in apple cuticle then rediffused back into the hypodermis, thereby causing damage. Hydroperoxides, auto-oxidative product from α-farnesene, have been thought to be the toxic compounds, inducing scald; however, it is not explained how the hydroperoxides move from the cuticle to the hypodermis. The identification and dynamic changes of 6-methyl-5-heptene-2-one as a natural volatile in apple fruit during ripening were made, which accumulated in higher quantitaty in cuticular wax than in headspace. The close relationship between the chloroplast breakdown and amount of α-farnesene changes, the induction of scald-like symptom on the surface of apple fruit by 6-methyl-5-heptene-2-one and the sensitivity of fruit to this ketone damage were investigated. Our results suggest that the accumulation of 6-methyl-5-heptene-2-one in the cuticular wax of apple fruit might be the causal reason for scald development in apples.