Fecha de publicación: 14/05/2020 Fuente: WIPO "varroa" The disclosure relates to a method for treating an active beehive infested with pests. The method includes delivery of an oligomeric polyester including polyol backbone units, diacid backbone units, and formic acid capping units. Hydrolysis of the oligomeric polyester in the beehive upon exposure to environmental water to release formic acid and diacid over time, which kill the pests. The released formic acid is a relatively volatile liquid, allowing it to reach pests essentially anywhere in the hive. The diacid (such as oxalic acid) is generally a non-volatile solid, but it can be transported throughout the hive via normal bee movement within the hive, thus reaching pests beyond the initial point of application.