Pollinators, such as bees, wasps, butterflies, and flies, can be exposed to pesticides by
- being hit by spray droplets during an application,
- contacting spray residues on treated plants, and/or,
- consuming a pesticide as nectar and pollen are collected.
Here are some ways to protect pollinators when pesticide applications are needed:
- Read the label carefully. Follow any specific requirements to protect pollinators.
- Avoid applying insecticides and fungicides to any plant in bloom.
- Be aware of your surroundings and weather conditions, especially wind speed and direction. Do not allow pesticide spray droplets to drift onto nearby flowering plants.
- Apply pesticides only after petals have fallen so flowers are less attractive to pollinators.
- If you must spray plants in bloom to save a crop, choose a pesticide/formulation with the lowest toxicity to bees and other pollinators.
- Organophosphate/carbamate, neonicotinoid, and pyrethroid insecticides have high residual toxicity to bees and other pollinators.
- Pesticide formulations affect residual toxicity of an active ingredient. Dust (D) > Wettable powder (WP) > Liquid (L) or Flowable (F) > Emulsifiable concentrate (EC).
- Use the lowest labeled rate. For example, the extended residual toxicity to bees of a particular pyrethroid insecticide is 1 day at the highest use rate; at the low rate it is 4 to 6 hours.
- Avoid using any systemic insecticide on plants even after bloom if that product lasts until next season’s bloom period. Imidacloprid persists; dinotefuran is active only during the current season.
- How to Reduce Bee Poisonings from Pesticides, PNW-591 (Pacific Northwest Extension) http://wasba.org/how-to-reduce-bee-poisoning-from-pesticides-pnw-591/
- Protecting Bees from Pesticides, SP-455 (Iowa State University Extension) http://iowatreepests.com/documents/SP455_Protecting_Bees_From_Pesticides.pdf
By Lee Townsend, Extension Entomologist