Don’t forget our friendly pollinators when using pesticides, reminds North Dakota State University Extension Entomologist Janet Knodel. Flowering field crops or weeds in the field are important food sources of many species of pollinators, including honeybees and native bees, she notes.

Bees are attracted to blooming field crops, such as canola and sunflowers, and even weeds like dandelions, wild mustard, white clover and goldenrod, in the field for nectar and/or pollen, she explains. 

“Remember, if you need to spray a flowering crop with insecticide or any other pesticide, please read, understand and follow the label and protect our pollinators against pesticide poisoning or spray drift,” Knodel says.

Knodel has good reason for the bee in her bonnet: North Dakota leads the nation in honey production. The value of bee pollination is estimated at $14.6 billion dollars in the United States.

“With the reduction in number of domestic and wild bee colonies due to colony collapse disorder and other diseases, the value of honeybees and native bees for pollination has increased,” she notes. “This increases the importance of protecting bees from pesticide poisoning.”

Of course, use of any pesticide in any way that is not consistent with label directions and precautions is illegal. It may also be ineffective and dangerous, she points out. The environmental hazard section of labels may include specific restrictions that protect bees while they are “actively visiting (foraging in field)” and “visiting (flying through a field).”

Can we get some shorthand for that? 

“Bees are actively foraging when there is daylight and temperatures are above 60 degrees Fahrenheit,” she says. “Because bees forage up to two-and-a-half miles or more from their hive, all beekeepers within two to three miles of the area to be treated with insecticide should be notified several days before the insecticide is to be applied.” 

The basic steps in reducing pesticide risks for pollinators are:

  • Know and communicate with beekeepers about hive locations;
  • Use economic thresholds and other IPM strategies. Economic thresholds ensure that pesticides are used only when crop losses prevented by pesticide use are greater than the cost of the pesticide and the application;
  • Use pesticides with low toxicity and low residual to bees. For example, avoid using dusts or wettable powder insecticide formulations because they generally are more toxic to bees; and
  • Evening or early morning applications are the least harmful to bees, because fewer bees are foraging.

Finally, never apply pesticides outdoors when winds are higher than 10 miles per hour, as it could cause spray drift problems, she notes.