Endosulfan exhibits low toxicity to bees and beneficial insects http://www.atsdr.cdc.gov/toxprofiles/tp41-c4.pdf ).
Endosulfan has relatively low toxicity to many species of beneficial insects, mites and spiders. These insects are beneficial in the sense that they prey upon pests which damage crops. Hence it is important that the insecticide used to kill pests is not unsafe to these beneficial insects. Other chemicals, necessarily substituted for endosulfan, would kill beneficial insects leading to population explosions of damaging pests which in turn would require more frequent sprays of harsher chemicals than if endosulfan had been used in the first place.