**Abstract**

The European or western honey bee, *Apis mellifera*, pollinates approximately 75% of crop species in agricultural and horticultural production systems worldwide at a value of \$170–\$200 billion per year. While foraging for pollen and nectar in flowering plants, honey bees may be exposed to insecticides; however, they may also be exposed to a multitude of other pesticides and compounds including: fungicides, insect growth regulators, herbicides, and adjuvants. Previous and recent studies show that these pesticides and compounds are directly or indirectly harmful to honey bees, which could negatively impact pollination and colony health. Fungicides can directly and indirectly affect honey bees, and enhance the toxicity (synergize) of certain insecticides, thus increasing their toxic effects to honey bees. Insect growth regulators negatively affect larvae, which impacts brood production in honey bee colonies. Herbicides can indirectly affect honey bee populations by reducing the availability of flowering plants, which decreases pollen and nectar sources during foraging, and consequently reduces colony survival during the winter. Adjuvants, especially surfactants, are a component of pesticide formulations, and are indirectly harmful to honey bees. This book chapter provides a detailed discussion of the effects of fungicides, insect growth regulators, herbicides, and adjuvants on honey bees.

**Keywords:** fungicides, insect growth regulators, herbicides, adjuvants, surfactants, synergism
