Publication 360, Fruit Production Recommendations: Bee Poisoning

Excerpt from Publication 360, Fruit Production Recommendations 2010-11, Order this publication

Table of Contents

1. Bee Poisoning
   • Table 11-3. Relative Toxicity of Pesticides to Honeybees
     • Group I: Pesticides highly toxic to bees
     • Group II: Pesticides moderately toxic to bees
     • Group III: Pesticides relatively non-toxic to bees
2. Related Links

Bee Poisoning

Bees are essential for the pollination of most trees and small fruits. Insecticides, many of which kill bees, are required for insect control but with careful management, both pollination and insect control can be achieved. Growers can protect bees by following these suggestions:

• Before applying a pesticide, advise local beekeepers so they can move colonies out of the danger area. Contact the Provincial Apiarist at 1-888-466-2372 ext. 63595 for a list of the beekeepers in the area or see www.ontario.ca/crops and click "Apiculture" for a list of provincial bee inspectors who know the local beekeepers.
• Do not apply insecticides while fruit trees are in bloom. The Bees Act makes it an offence to do so in Ontario. Do not spray any flowering crop on which bees are foraging and read the pesticide label for guidelines.
• Time insecticide applications to minimize bee poisoning. Daytime treatments, when bees are foraging, are most hazardous. Insecticide applications in the evening are the safest. Spraying after 7 p.m. allows the spray to dry before the bees are exposed to it the next day. This is the most successful way to avoid bee damage. Early morning is the next best time, but spraying should be completed before 7 a.m. Bees do not usually forage at temperatures below 13°C. If you plan to spray in the morning, contact beekeepers with bees within 1 km of your crop. The beekeepers will then have the option of taking protective action.
• Beekeepers can place wet bags in the entrance of the hive to disrupt the flight of the bees for up to 12 hours and provide more time for spray to dry. An opening of 2.5 cm (1 inch) on each side of the hive entrance is necessary so the bees can get out and ventilate the hive.
• Beekeepers should remove honeybee colonies as soon as pollination is complete and before any postbloom insecticides are applied.
• Honeybees are frequently poisoned by visiting weeds or cover crops, such as dandelions or clovers that are in bloom in the orchard or field. Clip or beat down such crops prior to a spray to help safeguard the bees.
• Do not apply insecticide on windy days to prevent drift toward any nearby hives.
• If there is a risk of honeybee poisoning, try to choose an insecticide that is not highly toxic to the bees from the list in Table 11-3. Relative Toxicity of Pesticides to Honeybees. When there is a choice, choose a product formulation that is less hazardous to bees. EC formulations are less toxic than WP formulations.

Table 11-3. Relative Toxicity of Pesticides to Honeybees, below, shows the relative toxicity of products used on fruit crops to honeybees as determined by laboratory and field tests.

Note: For more detailed information on the toxicity of specific pesticides to honeybees, refer to the pesticide label.

Table 11-3. Relative Toxicity of Pesticides to Honeybees

Group I: Pesticides highly toxic to bees

Severe losses may be expected if the following materials are used when bees are present at treatment time or within a few days thereafter.

Group II: Pesticides moderately toxic to bees

These can be used around bees if dosage, timing, and method of application are correct, but do not apply directly on bees, in the field or at the colonies.

Group III: Pesticides relatively non-toxic to bees

Related Links

• Integrated Pest Management (IPM)
• Apples in Ontario
• Berries in Ontario
• Tender Fruit in Ontario
• Grapes in Ontario
• Pesticide Application and Safety
• Pesticide Companies and Agents
• Search the PMRA website for labels