While commercial and hobby beekeepers search for tools to protect their hives, and orchardists and farmers turn to other pollinators such as the mason bee and hoverflies, we have our own part to play by reviewing our spray practices with honeybees in mind. Pesticides vary in their effect on bees. Contact insecticides affect the worker bee that is directly sprayed. Systemic insecticides can contaminate nectar or pollen.
Some pesticides have little effect on bees.
Some have little residual effect, so can be sprayed when bees are not active. Many are highly toxic to bees. Toxicity First a few generalities. Dusts are usually more hazardous than sprays. Granular pesticides seem to present little hazard.