New insecticidal cyclodepsipeptides from the fungus Isaria felina. I. Production, isolation and insecticidal properties of isariins B, C and D.

Three new cyclodepsipeptides related to the previously described isariin were isolated from a strain of Isaria felina. They were named isariins B, C and D. Isariin D and, to a lesser extent, isariin C, exhibited insecticidal activity against Galleria mellonella larvae, whereas isariin B and isariin itself proved inactive.