Related Rule
Colombia
Practice Relating to Rule 73. Biological Weapons
Colombia’s Basic Military Manual (1995) states that the use, production, possession and importation of biological weapons are banned. 
Colombia, Derecho Internacional Humanitario – Manual Básico para las Personerías y las Fuerzas Armadas de Colombia, Ministerio de Defensa Nacional, 1995, pp. 49–50.
Colombia’s Constitution (1991) prohibits the “manufacture, import, possession and use of … biological … weapons”. 
Colombia, Constitution, 1991, Article 81.
In 1995, in a ruling on the constitutionality of the 1977 Additional Protocol II, Colombia’s Constitutional Court stated in relation to the prohibition on the use of weapons of a nature to cause unnecessary suffering or superfluous injury:
Although none of the treaty rules expressly applicable to internal conflicts prohibits indiscriminate attacks or the use of certain weapons, the Taormina Declaration consequently considers that the bans (established partly by customary law and partly by treaty law) on the use of … bacteriological weapons … apply to non-international armed conflicts, not only because they form part of customary international law but also because they evidently derive from the general rule prohibiting attacks against the civilian population. 
Colombia, Constitutional Court, Constitutional Case No. C-225/95, Judgment, 18 May 1995, § 23.