This can be obtained as early as Virtuous Mission and could certainly be one of the earliest trophies you get for this game. There are only three types of fruit to collect and all of them can be found on your path to Sokolov.
1: Russian False Mango (Fruit B)
AREA: Dremuchij South
- After you claim your gear and get done with the COMM chat, take out your gun and look directly west from the tree you just climbed. In the branches of the tree near will be some fruit. Shoot one off and collect it.
2: Yabloko Moloko (Fruit A)
AREA: Dremuchij North
- First entering this area, progressing north you will come to a split heading further north or east. Head further north and look among the trees near the stump for some fruit. This should have a reddish tint to it which will help you recognize it when compared to Fruit C.
3: Golova (Fruit C)
AREA: Dremuchij North
- First entering this area, progressing north you will come to a split heading further north or east. Look up in the trees above the leaves you may have just traversed to get to this point and you should find some fruit. This will have a yellow tint, which will help you discern it from Fruit A.