Amos engaged in menial seasonal work as a nipper of sycamore figs, a variety considered food only for the poor. The practice of pinching,puncturing, or nipping the figs was to hasten the ripening and increase the size and sweetness of the fruit. See Amos 7:14

I had heard that there was often a worm in the fruit and this nipping was to get it out of there. Can you comment on this? fm

Yes, Amos was a nipper of figs of Sycamore as you may read at Amos Chapter 7. That was a seasonal job. Aside from that, he was a sheep keeper.

A nipper was a person who pinched off the unwanted blossoms,; the important thing is to understand that Amos was a humble, simple man. (and one of my favorite prophets) Read Your Bible!

*** Watchtower 07 2/1 p. 16 *** Amos—A Gatherer or a Nipper of Figs? BACK in the ninth century B.C.E., the prophet Amos was commanded by wicked Amaziah, a calf-worshipping priest, to stop prophesying in Israel. Amos objected, stating: “I was a herdsman and a nipper of figs of sycamore trees. And Jehovah proceeded to take me from following the flock, and Jehovah went on to say to me, ‘Go, prophesy to my people Israel.’” (Amos 7:14, 15) Yes, Jehovah sent Amos as a prophet; it was not his own idea. But what did Amos mean when he said that he was “a nipper” of figs of sycamore trees? The Hebrew expression so translated appears just this one time in the New World Translation. Other Bible translations render the term “gatherer,” “cultivator,” “dresser,” or “grower,” rather than “nipper,” of sycamore figs. However, the journal Economic Botany says that an appropriate translation of the term would be “piercer” because this word indicates a special action of the cultivator of sycamore figs. The practice of nipping, or piercing, that is, making small gashes in sycamore figs, has been well-known in Egypt and Cyprus since very early times. Piercing, or nipping, is no longer practiced in modern-day Israel because other varieties of figs are grown in that land. However, nipping was practiced by the Israelites in Amos’ day, since the sycamores that grew in Israel at that time descended from the Egyptian varieties. Apparently, piercing figs makes them absorb water and become juicy. It also increases the production of ethylene gas, which accelerates the ripening process, resulting in larger and sweeter fruit. In addition, parasite wasps do not spoil the fruit because it ripens rapidly. In spite of his lowly background as a shepherd and a nipper of figs, Amos was not intimidated by his enemies. Rather, he courageously declared Jehovah’s judgment message against Israel. What a fine example for God’s servants today, who must likewise declare an unpopular message!—Matthew 5:11, 12; 10:22.