Place the pie crust into a 9-inch pie plate, and crimp the edges.
Add all of the berries to a large bowl, and sprinkle with lemon juice. Combine the sugar and tapioca. Add to the berries; toss gently to coat. Let stand for 15 minutes. Spoon into the pie crust.
In a small bowl, combine the flour and sugar. Cut in the butter until crumbly. Sprinkle over the filling. Bake for 45 minutes or until the filling is bubbly and the topping is browned. Cool on a wire rack.