Effects of fungicide sprays during apple bloom on pollen viability and honey bee foraging [Malus domestica, Apis mellifera]

Fungicide applications were made during apple, Malus domestica Borkch., bloom to determine the duration of fungicide effects on pollen viability in the field and whether spray applications affect the foraging behavior of honey bees, Apis mellifera L. Fungicide sprays did not affect the numbers of honey bees foraging on trees or their foraging behavior. Mean percent pollen germination was depressed to levels between 12.2 and 31.1% by captan and to 29.5% by Dikar 2 h after spray application. Recovery of pollen viability required 24 to 48 h, depending upon orchard conditions. Benlate, Polyram, Baycor, and Topsin-M had no significant effect on pollen viability. The rapid recovery of pollen viability after initial spray applications and the lack of effect on flower visitation by bees indicate minimal effects on pollination or fruit set under most conditions.