Fruit Trees

Living in the South of Italy,fruit trees are in abundance,but unfortunatley not in my garden. Who ever planned this one thought pine trees were better!! I do not agree. They are messy and poison the ground.
Earlier this year we bought some fruit ,plum,lemon,orange,pear,cherry,and one by one they seem to be dying. Any ideas as to why? They are regularly watered. They are not close to any pine either.
Help!