Time to go Organic!
Pesticides vary in their effects on bees. Contact pesticides are sprayed on plants and can kill bees when they crawl over sprayed surfaces or other areas around it. Systemic pesticides are usually incorporated into the soil/onto seeds and move up into the stem, leaves, nectar & pollen of plants.
Contact pesticides tend to be more hazardous to bees than solutions or emulsifiable concentrates. When a bee encounters pesticides while foraging, the bee may die immediately without returning to the hive. In this case, the queen bee, brood, and nurse bees are not contaminated, and the colony survives. Alternatively, the bee may come into contact with an insecticide and transport it back to the colony in contaminated pollen or nectar or on its body, potentially causing widespread colony death.