Change the period of application
Description of the measure
The most important routes of exposure of pollinators to pesticides is direct overspray of the insects in the crop during treatment, and the uptake of contaminated nectar and pollen from flowering crops.
In general, a crop is attractive to bees when it is flowering, or when weeds in the crop are flowering. Crop attractiveness to bees is further discussed in the Assessment Methods module.
A regulator may allow registration of a pesticide that is hazardous to pollinators, under the condition it is not applied during flowering of the crop or flowering of weeds in the crop.
This measure is often communicated by a precautionary phrase on the pesticide label, such as:
"To protect bees and other pollinating insects do not apply to crop plants when in flower"
or
"Do not use where bees are actively foraging”
or
"Do not apply when flowering weeds are present”
Conditions for effective implementation
The target pest should not be present during flowering of the crop (or flowering of the weeds in the crop).
The pesticide should not be systemic, because application of systemic pesticides before flowering could still lead to pesticide residues in pollen or nectar during flowering.
Estimated risk reduction potential
This measure should, in principle, lead to an almost complete reduction in risk.
Potential constraints
The attractiveness of a crop for pollinators may be influenced by factors other than its flowers, e.g. the presence of honeydew-producing aphids. In such cases, avoiding pesticide applications during flowering may not exclude all risks to pollinators.
Further information
Hazard assessment for honeybees is discussed in the Assessment Methods module.
Further information on pesticide risk reduction for bees can be found in the MAgPIE workshop report – Mitigating the risks of plant protection products in the environment. Society for Environmental Toxicology and Chemistry (SETAC)) {INSERTLINK as soon as we have one}