Certain derivatives of avermectin, avermectin monosaccharide and avermectin aglycone, having on the 4″, 4′ or 13 position, respectively, a 6-membered cyclic acetal with a substituent on position 2, that are useful in controlling pests, in particular pests that are harmful to crop plants and to its propagation material, such as representatives of the class insecta, the order acarina and the class nematode, are provided.