A statement in your syllabus can be a first step in creating an atmosphere of integrity and in making your expectations clear. Consider highlighting the importance of integrity to your course, what you expect, and consequences. Here is a syllabus example from History professor Ann Moyer :
Academic honesty is fundamental to our community. The PennBook contains our Code of Academic Integrity. A confirmed violation of that Code in this course will result in failure for the course.
Additional Samples