Size and location are good indicators; fruit buds are larger, or fatter – housing a flower cluster. Vegetative, or “leaf buds” are smaller and tighter. Buds on “last seasons” (one year wood) growth are generally all “leaf buds.” Fruit buds begin to form the following year, but not from every leaf bud.

http://www.rickerhill.com/Prunin6.gif

Most apples develop Fruit spurs, they may take 3 to 7 years to develop and will produce multiple flower clusters. When pruning, leave all fruit spurs alone. If ‘heading’ back a branch when pruning, take it back to a downward facing “leaf bud” or shoot; never dead-end a branch at a fruit spur. Here’s a fruit spur:

http://web1.msue.msu.edu/fruit/images/apslvtpl.jpg

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