Preheat the oven to 350 F (180 C) and grease a loaf pan (standard size). Set aside.
In a large bowl, mix the first 4 ingredients together, from the vegetable oil to the vanilla extract.
In a small bowl, mix the dry ingredients together, from the baking powder to the all-purpose flour.
Pour the wet ingredients into the dry ingredients, and then add the watermelon, strawberries and pear. Mix just enough to incorporate the dry ingredients, and pour the batter into the prepared pan.
Bake for 1 hour. Remove from the oven, and let cool for 15 minutes before removing the loaf from the pan. Let cool completely before slicing bread. Keeps well for 2-3 days at room temperature.