Bee Pollination of Crops in Ohio

Bulletin 559

Manipulate Bees for Crop Pollination

A. One mistake often made by a fruit, vegetable, or seed producer regarding bee pollination is to assume that "the neighbor's bees" will provide sufficient pollination of his crop. There are several reasons why a producer who does this can be disappointed at harvest time with low yields:

1. Although honeybees from a single hive will fly 2 to 3 miles from the colony, the radius of greatest efficiency and greatest pollination is only 200 to 300 yards from the colony. The reason for this is mathematical, because the farther away from a colony a bee flies, the greater the number of acres it can potentially visit.

2. There are many flowers competing for the bee's attention; some may be more attractive or "profitable" to work than the crop needing pollination. Bees will not fly a great distance to forage on an unattractive crop.

B. By moving bees directly into a field, a grower can increase the flight activity in that area. However, there are several considerations he should make, and procedures he should follow:

1. Colony arrangement: Bees are most efficient when closest to the colony; therefore, to achieve the most efficient distribution of foragers, the colonies should be distributed at 300 to 500 yard intervals. Inexperienced foragers work closer to the hive, then disperse with age and experience.

2. Some crops or specific varieties of some crops are unattractive to bees. In such cases, a solution is to flood the area with bees. Sugar sprays and attractants have failed to increase pollination.

3. Provide water for bees to minimize wasted effort by foragers.

Protecting Bees from Pesticides

Until better methods of covering or otherwise protecting bees during insecticide sprays are developed for use under the humid conditions in Ohio, the only safe way to protect honeybee colonies is to remove them from the area of the spray. This is difficult, or impossible in some situations, particularly if a large number of acres are to be sprayed (as for mosquito control or gypsy moth), or if many hives are involved.

USDA suggests that beekeepers cover hives with burlap during insecticide sprays and keep the burlap wet. This method has been only moderately successful in Ohio, perhaps because bees are too hot and humid under the burlap. Confining bees to the hive by screening the entrance and the top after removal of the inner cover might prevent overheating and minimize losses, as long as there is no direct hit by the insecticide on the open colony.