What's wrong with my cherry tree?

[chakka35]

My cherry tree is quite young but it has borne fruit for the last two or three years. The trouble is that as soon as the fruit turns from pale yellow to red it shrivels up and drops off. What sort of disease or pest can this be?

[rowanwitch]

erratic watering with a young tree might be part of it, doesn't sound like a pest/diseasee

[chakka35]

Thanks.