My neighbor is dusting his squash in the garden with the new equivilant of seven dust although it has a new name. how dangerous is this for my bees? I am not blaming him for taking care of his garden.
It should not wipe out your hive, but it could kill some of the foragers working those plants and or the larva that may be fed that pollen. I am sure others will give you more specifics!
Bees seem to find other food sources than squash most of the time.
Sevin (carbaryl) is highly toxic to all insects. It is a kill on contact.
Hand him a bottle of insecticidal soap. Works much better. It will kill honey bees if sprayed directly on them but no residual effects.