Margaret Holm
We’ve all heard that honey bees and native bees are in trouble in North America. There seem to be a number of factors leading to the decline of native pollinator populations of honey bee colonies. Minute quantities of neonicotinoid pesticides have been implicated in bee population decline and have been banned in many European countries. The second factor severely affecting honey bees is the Varroa mite. A third factor may relate to poor nutritional opportunities for bees feeding on monocultures of some commodity crops. Recent drastic declines in some native bumblebee populations have lead researchers to hypothesize that diseases were spread from non-native bumblebees used in greenhouses.
Both wild and domestic bees provide millions of dollars of pollination services to fruit and ground crops. Although they are not needed for grape pollination, they do pollinate cover crops and plants that support beneficial insects. Maintaining a healthy population of insect pollinators is vital to agricultural production and the environment.
Use of pesticides is a part of most farm operations, however good management practices can ensure that bees have little or no direct contact with toxic sprays. Consider the following before applying pesticides.
Are you practicing Integrated Pest Management by correctly identifying the pest problem and applying treatment at the lowest effective label rate?
Have you checked pesticide options available and the toxicity of the product to bees? Check the label, the Pest Management Regulatory Agency (PMRA) web site, or get advice from field services staff and your local pesticide supplier.
Do you know the location of beehives owned or being used for pollination by neighbouring agricultural properties? If they are nearby, contact the bee-keeper about your spraying plans.
Have you planned your spraying to avoid the time when bees are most active? Remember that native bees are active at lower temperatures than honey bees.
Avoid flower bloom times – for crops, cover crops, and flowering weeds – when bees are attracted to your property. One option is to remove flowers before pesticide application by mowing.
Are you using techniques to reduce pesticide spray drift? Air-blast sprayers can produce finer droplets with greater drift potential. Consider redirecting or turning off nozzles, or use technologies that reduce drift. Have you tested or calibrated your nozzles this year?
Are you carefully considering wind and temperature conditions before spraying to reduce spray drift?
Go to the Health Canada site and search for “Protecting Pollinators during Pesticide Spraying” for more tips on best management practices. Be aware that pollinators collect pollen and water as well as flower nectar and can be harmed by pesticide residue from these sources. Ground-nesting bumble bees are also very susceptible to pesticides used in turf management.
You can support bees by providing areas of native habitat or buffer crops of clover and other flowering plants that are not sprayed. Minimize tillage in natural areas and leave gullies and hedgerows which are ideal nesting and foraging habitat. Weathered wood such as fence posts, sheds and trees offer homes to many native pollinators such as mason bees. Native bumble bee and mason bee species are more efficient pollinators than honeybees and are active longer when the weather is cold and wet. They need very little in return for their services—a small hole to nest in and native habitat to support them after the commercial crop has blossomed.