It won't hurt the basil (if applied appropriately so the leaves don't burn)...but it might add a bit of weirdness to the flavor if not fully rinsed upon harvest (or the rain hasn't washed residues off).

Planting basil with tomato is a great idea! What I did was plant a row of alternated tomato and peppers plants, and then at the end of the entire row I planted about 10 basil plants. That way, I can get the companion benefits from the plants that are in the row with the tomatoes and peppers, but then there's a giant bush growing at an easily accessible spot where I can harvest fresh basil.

Planting basil with tomato is a great idea! What I did was plant a row of alternated tomato and peppers plants, and then at the end of the entire row I planted about 10 basil plants. That way, I can get the companion benefits from the plants that are in the row with the tomatoes and peppers, but then there's a giant bush growing at an easily accessible spot where I can harvest fresh basil.