Bees and Pesticides in the Garden" is the title of a recent article by Ric Bessin, Extension Entomologist at the University of Kentucky. Anyone who grows fruits and vegetables knows the importance of pollinators for pollinating crops and insuring a bountiful harvest. In addition, the ability of bee colonies to survive from year to year has been declining for the past decade due to a variety of causes. One of which is pesticide contamination. The following are Ric Bessin's suggestions for gardeners to reduce bee contact with insecticides in your gardens.
Bees can be harmed by spray drift moving toward or over them or their colonies. Avoid spraying pesticides on windy days. In other words, do not spray pesticides when winds are in excess of 10 miles per hour. Read the pesticide label, use the labeled rate and follow any guidance on spray drift reduction. To avoid accidentally spraying bees, spray after 6 pm or when temperatures are below 55˚F, since bee foraging is greatly reduced.
Next, avoid contaminating the bees' food and water sources. Bees need a constant source of water, especially in the heat of the summer to cool their hives. As a general rule of thumb, you should not spray plants in bloom with an insecticide (many pesticide labels expressly prohibit this) or in areas where pollinators are foraging. This includes weeds, since many are the primary food source for bees in the spring of the year. Take note of bird bath locations and other likely water sources for your local pollinators.
Finally, only use pesticides when necessary and use effective pesticides with the least toxicity to bees. Products containing Bt or Bacillus thuringiensis are among the insecticides least toxic to honey bees.
Purdue University's "PROTECTING HONEY BEES FROM PESTICIDES" is a very handy publication when selecting which effective pesticide to use that does not injure your local pollinators. It categorizes the toxicity of pesticides with regard to honeybees into 3 categories: Highly Toxic Pesticides; Moderately Toxic Pesticides; and Relatively Nontoxic Pesticides.
Bees can be harmed by spray drift moving toward or over them or their colonies. Avoid spraying pesticides on windy days. In other words, do not spray pesticides when winds are in excess of 10 miles per hour. Read the pesticide label, use the labeled rate and follow any guidance on spray drift reduction. To avoid accidentally spraying bees, spray after 6 pm or when temperatures are below 55˚F, since bee foraging is greatly reduced.
Next, avoid contaminating the bees' food and water sources. Bees need a constant source of water, especially in the heat of the summer to cool their hives. As a general rule of thumb, you should not spray plants in bloom with an insecticide (many pesticide labels expressly prohibit this) or in areas where pollinators are foraging. This includes weeds, since many are the primary food source for bees in the spring of the year. Take note of bird bath locations and other likely water sources for your local pollinators.
Finally, only use pesticides when necessary and use effective pesticides with the least toxicity to bees. Products containing Bt or Bacillus thuringiensis are among the insecticides least toxic to honey bees.
Purdue University's "PROTECTING HONEY BEES FROM PESTICIDES" is a very handy publication when selecting which effective pesticide to use that does not injure your local pollinators. It categorizes the toxicity of pesticides with regard to honeybees into 3 categories: Highly Toxic Pesticides; Moderately Toxic Pesticides; and Relatively Nontoxic Pesticides.