Pesticide Registration Toolkit

#1035 Effects on bees - honeybee - chronic toxicity

Objective of the study

This study is designed to assess the chronic acute toxicity of pesticides to honeybees. Newly emerged worker bees are repeatedly exposed to known concentrations of the pesticide in their food, for a period of 10 days. The chronic toxicity study for honeybees is a relatively new data requirement for pesticide registration, and testing methodologies have not yet been internationally adopted.

Circumstances under which the study is recommended to be required

Data with the active ingredient are recommended to support all outdoor end-use product uses, including turf. Data are generally not recommended to support end-use products in the form of a gas, a highly volatile liquid, a highly reactive solid, or a highly corrosive material. This study may also not be required in situations where bees are not likely to be exposed, including (but not limited to): food storage in enclosed spaces; soil applications with non-systemic pesticides (except granules, which may release dust if drilled); non-systemic dipping treatments for transplanted crops and bulbs, non-systemic rodenticidal baits; use in greenhouses without bees as pollinators.

Test organism

The study is conducted with newly emerged worker honeybees (Apis mellifera).

Test substance

  • Technical grade active ingredient

Typical endpoints of the study

  • Mortality: oral LC50 (μg a.i./kg and mg a.i./bee/day)
  • No observed adverse effect concentration (NOAEC) (μg a.i./kg and mg a.i./bee/day)
  • Other biological effects observed or measured, e.g. abnormal behaviour of the bees, rate of consumption of diet in treated and untreated groups, development of hypopharyngeal glands.

Test guidelines

No internationally adopted guidelines are available yet for the chronic toxicity study with honeybees. Until then, the following guidance may be used: