"It's a pump-action spray. There's plenty of Insecticide inside."
This insecticide is lethal to the bees and their massive hive found in the Gallery of the Dormitory. In Chris Redfield's mode of Resident Evil, it is found on the corpse in the Gallery, who had clearly been stung to death before he could use it. Use the spray on the beehive by spraying it into the hole where you found the residence map
There are two types of Insecticide spray.
The first is a pump-action spray, the second is a spray can.