The Dink Network

Johan or Jack's wife tells me that a bonca ate her husband and the walkthrough says north of the apple tree, but i started the game 2 times and i see no boncas.

I think you may have missed an exit. You can go north in the screen with the "bush" at the top, by walking through that bush (which is actually the top of a tree).

The bonca should be in the screen you then enter (which has a wall on its north side).