Related Rule
Israel
Practice Relating to Rule 73. Biological Weapons
Israel’s Manual on the Rules of Warfare (2006) states:
In 1925, the countries of the world gathered in an international congress in Geneva and signed a protocol completely banning the use of chemical and bacteriological (biological) weapons. All the leading countries in the world signed the Protocol, with the exception of the United States and Japan. Today, 133 countries have signed the Protocol, and its provisions are considered to be overriding, that is to say that they are binding on every country in the world, including those that never signed the Protocol. 
Israel, Rules of Warfare on the Battlefield, Military Advocate-General’s Corps Command, IDF School of Military Law, Second Edition, 2006, p. 18.
The Manual on the Rules of Warfare (2006) is a second edition of the Manual on the Laws of War (1998).