Coulure: During flowering in the spring, wind and rain as well as chemical deficiencies can keep grapevine flowers from being properly fertilized, causing these flowers to drop off the cluster. This dropping of flowers is called coulure, or shatter. Since each flower is responsible for a grape, the cluster of grapes that eventually forms is loose and missing grapes. If the improperly fertilized flower stays attached, it produces a puny, seedless grape called a "shot" grape. Although the yield is reduced, there is a corresponding benefit—loose clusters that allow for increased air circulation are less susceptible to rot in humid conditions.

落果：在春天葡萄植株的花期，风雨以及植株体内化学产物分泌不足会阻碍葡萄花完全受精，使果穗上的花减少。这种花量的减少称为落果，或落花。虽然每朵花都会发育成果实，但葡萄果穗需要变得松散并且减少果实数量。如果没有受精的花依然与果穗保持相连，就会发育成小而无籽的果实，称为“无籽果实”。尽管这样葡萄的产出收益降低，但也会带来相应的利益：松散的果穗可以提高果实周围的空气流动，使果实不容易在潮湿的环境中感染腐烂。