How can farmers, gardeners and applicators reduce risks of honey bee injury from pesticide applications?

Bee Health, Pesticide Environmental Stewardship August 16, 2013|Print

Do not treat fields in bloom. Be especially careful when treating crops, such as alfalfa, sunflowers and canola, which are highly attractive to bees. Insecticide labels carry warning statements about application during bloom. Always read and follow the label. Examine fields and field margins before spraying to determine if bees are foraging on flowering weeds. Milkweed, smartweed and dandelion are examples of common weeds that are highly attractive to honey bees. Where feasible, eliminate blooming weeds by mowing or tillage prior to insecticide application. While bright and colorful flowers are highly attractive to bees, some plants with inconspicuous blossoms such as dock, lambsquarter and ragweed also are visited. When examining areas for blooming plants, consider all blooming plants. It is also important to be aware that many plants only offer pollen and nectar for a few hours each day. Fields should be scouted for bees at the same time of day as the anticipated insecticide application. Choose short residual products and low hazard formulations. If insecticides must be applied during the flowering period to save a crop, select the least hazardous option. Avoid spray drift. Give careful attention to the position of blooming crops and weeds relative to wind speed and direction. Changing spray nozzles or reducing pressure can increase droplet size and reduce spray drift. Apply insecticides when bees are not foraging. Some insecticides can be applied in late evening or early morning (i.e. from 8 p.m. to 6 a.m.) with relative safety. In the case of corn, bees collect pollen from tassels in the early morning and are not present in the afternoon or evening. Short residual materials applied from late afternoon until midnight do not pose a bee hazard in corn fields if blooming weeds are not present. Adjust spray programs in relation to weather conditions. Reconsider the timing of insecticide application if unusually low temperatures are expected that night. Cool temperatures can delay the degradation process and cause residues to remain toxic to bees the following day. Stop applications when temperatures rise and bees re-enter the field in early morning. Contact local beekeepers and obtain locations of bee yards. Many state law requires that apiaries be clearly identified with the name, address and phone number of the beekeeper. Identification may appear on one or more colonies, or a separate sign may be posted in the apiary. Some state departments of agriculture maintain a list of apiary locations and can help identify the owner. If colonies are present in an area that will be sprayed with a bee-toxic insecticide, contact beekeepers in time for them to protect or move the colonies. Many pesticide applications pose minimal risk to bees, and beekeepers may choose to accept some risk rather than move colonies. Notify beekeepers as far in advance as possible. Read the pesticide label. Carefully follow listed precautions with regard to bee safety. Maintain bee forage areas. Intensive agriculture often increases bee dependence on cultivated crops for forage. Encouraging bee forage plants in wild or uncultivated areas will reduce bee dependence on crop plants that may require pesticide treatments. Plants recommended for uncultivated areas include sweet clover, white Dutch clover, alfalfa, purple vetch, birdsfoot trefoil, and partridge pea. Most trees and shrubs are beneficial to bees. The most attractive include linden, black locust, honey locust, Russian olive, wild plums, elderberries, red maples, willows, and honeysuckle. Soil conservation, natural resource and game managers usually are eager to help establish plantings that benefit bees. These areas also conserve soil and provide valuable habitat for plant and wildlife conservation programs. - Marion Ellis, University of Nebraska