Here is the sentence again:
During the summer when a variety of fruit is in season, Melville always
avoids the fresh peaches, the fuzzy skin
brushing against his lips makes Melville think that he's eating a small
rodent.
The comma between peaches and the creates a comma splice. Melville always avoids the fresh peaches is one complete sentence. The fuzzy skin brushing against his lips makes Melville think ... begins a second complete sentence.
To fix this problem, you could put a period after peaches and capitalize the T for the.