Bumble Bees

bumble bee and carpenter bee TThe common name of bumblebee possibly comes from their large appearance and/or the buzzing sound they make as they fly. Bumblebees are typically found in flowering plants, and they can sting. Bumble bees rarely nest in structures.

Often confused with carpenter bees, bumble bees are characterized by the hairiness of the abdomen (carpenter bees have a smooth abdomen). (Carpenter bees can be observed around and under eaves, decks, breezeways, etc. They drill holes in the exterior of the wood to lay eggs.)


Bumble Bee Appearance

  • Size: Adult worker bumble bees measure in body length about 1/4-1" (6-25 mm), queens about 3/4-1" (17-25 mm) long .
  • Color: Black with yellow (rarely orange) markings; with overall fuzzy appearance, including top surface of abdomen.

Bumble Bee Biology

Bumblebees are social insects which live in nests or colonies. The adults are represented by workers which are sterile females, queens, and males (drones) which come from unfertilized eggs and usually appear in late summer.

Typically, only inseminated queens overwinter and do so underground. During the spring, bumblebee queens select a suitable subterranean cavity or surface grass clump as a nesting site and lay eggs.

Mature bumble bees nests ultimately contains about 50-400

Bumble Bee Habits and Habitats

As social insects, bumble bees live in colonies. Each spring a queen that has survived over wintering will find a suitable nesting site and establish her colony. Her first brood of eggs mature into workers that forage on pollen and nectar for food.

The workers do produce honey, but it is not edible to humans.

The bumble bees colony grows larger over the summer and is usually discovered while gardening or mowing the lawn. The bumble bees will attack to defend their nest, so they are considered a health concern.

They forage when temperatures are below 50 degrees F (10 degrees C; lowest observed flight at 26 degrees F/-3.6 degrees C) whereas, most bees stop foraging at 61 degrees F (16 degrees C).

Each worker forages independently, and bumble bees never exchange food. Old cocoons are used to store both pollen and nectar. Only enough food (honey and pollen) for a few days is stored at any given time which helps discourage nest predation by skunks, foxes, etc.

During the fall, the colony produces a number of queens that fly out to find protected sites to spend the winter and thus repeat the cycle next year.

Bumble bees don't make holes or tunnels in wood, but will nest in abandoned rodent burrows, under piles of grass clippings or leaves, stones, logs, ect.
Occasionally, bumble bees will establish a nest above ground in a wall, firewood pile, shed, crawl space or attic.

People sensitive to insect venom should exercise care around bumble bees and their nests.

Bumble bees are considered beneficial insects because they pollinate the flowers of many plant species. However, if their nest is located in or close to an occupied structure or recreational area, then control is needed.

Bumblee Bee Control

To prevent bumble bees from establishing nests on a property, fill in all animal/rodent burrows and holes in the soil.

Seal holes in the building's exterior and ensure that all vents have tight-fitting screens.

Bumblebees are considered beneficial insects because they pollinate the flowers of many plant species.

  1. During the day find the location of each nest by observing where the bees disappear into the ground, grass clump, or structure.
  2. At night using low background light and while wearing a bee veil, apply an appropriately pesticide.
    • Using an aerosol like D-Force HPX would give a quick knockdown and a residual for 8 weeks. D-Force HPX has the active ingredient Deltamethrin. The deltamethrin is also in D Fense Dust which has a longer residual time.
  3. Dusts, such as D Fense Dust work well when applied around and into the the nest area . The dust particles are designed to flow back into the area. D-Fense Dust is designed to last for 6 months and will kill quickly. It is advisable to use plenty of dust to dust thoroughly into the nest area. There may be hatch outs, further hatching of eggs.
    • Using a duster with an extension such as the B&G 1150 Dust-R with extension tips may make the job easier.
    • If dusting structural nest with D-Fense Dust, but do not seal the entrance until late summer or early fall, when all hatching has been completed.

I have a problem with bees around my house. They come back each year and build a nest in different locations. What is the best way to discourage them from returning to my house?

Bees leave behind a scent that is very powerful and attracts new bees to the area. When a hive is removed, you need to clean the area with strong disinfectants and spend a good bit of time sealing the openings around the outside with silicone caulk. The rule of thumb is: remove the bees and seal the entire side of the building. If you can slip a piece of paper into a crack, caulk it.