Home & Garden Tips
Bees and Pesticides
By Roosevelt McWilliams County Extension Agent

Many insects visit flowers to collect pollen and nectar as food. As they forage, these insects spread pollen grains among flowers, accomplishing pollination. Many flowers offer sugary liquid nectar as an added enticement for pollinating

insects. Among insect pollinators,

bees are especially efficient because they eat pollen and nectar exclusively, visit many flowers of the same species during a single trip, and have hairy bodies which easily pick up pollen grains.

There are over 3,000 species of bees in North America. Most of these are solitary bees, but a well known minority is social, that is, they live together in colonies and cooperate in colony tasks. Both solitary and social species are important in crop pollination but the social species namely honey bees and bumble bees are more easily managed.

Compared to honey bees, some wild bees pollinate certain crops more efficiently because of unique and desirable behaviors. For example, Southeastern blueberry bees buzz-pollinate blossoms by shaking pollen from the flower with high frequency muscle vibrations. This greatly improves blueberry pollination efficiency.

In many parts of the country, fruit and vegetable growers are concerned about declining numbers of wild bees. Human activities destroy bee habitat and forage. In short, growers are receiving less free pollination from wild bees and increasingly they must make up for this by renting managed honey bee hives during bloom periods.

A bee hive is made up of stacked boxes called supers. As colonies grow during a season, beekeepers add supers to accommodate the growing bee populations and honey stores. A very tall hive is probably strong, but unscrupulous beekeepers may stack empty supers on weak hives to make them look strong. Don't rely on external appearances.

When the lid is removed, bees should immediately boil over and blanket the tops of six to eight combs. There should be at least five combs with brood. When brood is young, you can see glistening white larvae in their cells, but older brood is covered with cardboard looking wax capping. Bees are best motivated to collect pollen when they have young, uncapped brood. Strong colonies with large populations and plenty of brood are superior pollinators, and the beekeeper should get a higher rental fee.

Most bee poisonings occur when bees visit flowers that were treated with insecticide. This kind of exposure is more hazardous than a direct spray on hive. With fast acting toxins, foraging bees are killed in the field. However, slower acting toxins are even more hazardous to a colony because foraging bees survive long enough to return to the hive with contaminated pollen which enters the food supply and kills young bees for weeks. Such hives either die outright or become worthlessly weakened for the rest of the season.

As a rule, never spray a plant that is flowering. However, many crop plants bloom in cycles which make it difficult to use insecticides without risk to bees. Fortunately, there are still ways to reduce bee kill. First, not all insecticides are equally hazardous to bees. Some pesticides are listed according to their relative bee hazard. You should look for a product labeled for the target pest, with low bee toxicity and with a short residual time.

Secondly, granules and solutions are safer than wettable powders and dusts. Finally, many insecticides are deadly to bees when they are first applied but degrade within hours and are safer than wettable powders and dusts. Since bees only forage in daylight apply bee hazardous pesticides in early evening. By morning the insecticide has controlled the target pests, but the residues are reduced and risk to bees is minimized.

We will have our bi-monthly beekeepers meeting 7 p.m., Monday, Sept. 24, at the Burke County Office Park Kitchen. Dr. Keith Delaplane, Entomologist Specialist from Athens, will be the speaker. The public is welcome to attend the meeting.