For reasons that are not yet clear tome, this has been a good year for bumble bees. In my own yard,bumble bees have been more noticeable as they forage for nectar from flowers of bee balm, St. Johnswort and other plants.
Bumble bees are big, fuzzy insects recognized by almost everyone by their robust shape and black and yellow coloration.The common species are 3/4 inch in length or more. Like their close relatives the honey bees, bumble bees live in a colony where the adults care for the young (larvae) produced by a single queen.Bumble bee nests are small compared to honey bees, as each nest contains only a few hundred individuals. Also unlike honey bees,a bumble bee nest is annual and is used only one year and then abandoned.
Bumble bees usually nest in the ground in a deserted mouse nest or bird nest. Occasionally they nest in cavities within a wall or even in the clothes drier vent.
In the spring, the queen selects a nest site and starts the colony by lining an existing cavity with dry grass or moss. Then she collects a mass of pollen and moistens this with nectar to produce a stored food called "bee bread." Her first brood of offspring, numbering 5 to 20, will all be workers (daughters) who take over the colony responsibilities of nest enlargement, food gathering and storage, and feeding and caring for the larvae. The queen continues to lay eggs throughout the summer. By late summer,reproductive males and females are produced. These mate on the wing and the fertilized females move to hibernation sites in the shelter of loose bark, hollow trees or other dry, protected places to lie dormant through the winter. The males and workers still in the colony die with frost or the first hard freeze.
Along with the honey bees, bumble bees are very important pollinators of flowers. Certain plants are better pollinated by bumble bees because of their very long tongues.
If the vicinity of a bumble bee nest can be avoided, then leaving them alone and waiting for them to die in the fall would be the preferred management option. However, bumble bee nests are often found in yards, flowers beds, wood piles, or walls in high traffic places where the threat of being stung is great.
Trapping bumble bees is not practical and exclusion techniques may not solve the problem. When controlling bumble bees is necessary, using insecticides to poison bee colonies is the control method of choice.
Bumble bees, honey bees and yellow jackets are all controlled the same way. After determining the nest location and nest entrance during the day, wait until night to treat if possible. Wear long-sleeved shirt and trousers and tie sleeves and pants legs shut or pull your socks out over your pant cuffs.
Apply insecticide through the entrance hole. Dust formulations of insecticides are preferred (e.g., Sevin dust). Use a duster or "fling" insecticide into the hole off an old plastic spoon. Sprays and ready-to-use"wasp and hornet" aerosol sprays can also be used, but often with less satisfactory results.
Do not plug the entrance hole until all activity has stopped.Be prepared to repeat the treatment if necessary. Finally, seal shut, caulk and paint all openings in the vicinity of the old entrance.
If the nest opening can not be reached because of shrubs or other obstruction, the area of bee coming and going (observed carefully from a distance during the day) can be broadcast sprayed at night with an insecticide solution to kill the foraging workers.
This article originally appeared in the August 25, 1993 issue, p. 143.
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