Bees: Identification, Benefits and Controls

Bees: Identification, Benefits and
                      Controls
                                   By Cornelius Tarver

                            Cobb County Horticulture Agent

One mention of bees generally makes people think of one thing. Sting! However, if people
understood a little more about these amazing insects they would be less inclined to fear
them.

Most people think well of honey bees for pollinating flowers and making honey but that’s
the extent of any good feelings towards them. However many other varieties of bees besides
honey bees are valuable as pollinators too. Some are also beneficial in ways they are not
normally recognized for such as predators on insect pests and as soil aerators.

                     Honey bees, Apis mellifera, are the most important crop pollinators.
                     They are responsible for $2 – 9 billion added value to American food
                     production annually. Honey bees are the classic social insect. They
                     live in hives with a single queen and workers which can number up to
                     60,000. Honeybees will sting when defending their hive but are
                     generally non-aggressive. Only the female worker bees can sting and
                     they can only sting once after which the bee will die. When defending
                     the hive stinging honeybees will swarm so a person can still be stung
                     multiple times by multiple bees.

The honey bee population has been steadily declining over the past 15 years. Some of that
decline is attributed to two types of mites, the varroa mite and the tracheal mite, which are
parasites of honeybees. The other threat to honeybees is an emerging phenomenon termed
Colony Collapse Disorder, CCD, which is causing the demise of many domestic beehives.
The varroa and tracheal mites can be treated in domestically kept beehives, but there’s no
protection for feral, or wild, beehives. On the other hand, CCD is a problem for domestic
beehives but doesn’t seem to affect feral beehives.

Bumble bees, Bombus sp., are also important pollinators. They are
also social insects with a single queen and workers but their colonies are much smaller in
number than those of honey bees. Bumblebees make their nests in the ground and don’t
produce honey.

Bumblebees are black and yellow with hairy bodies 3/4” – 11/2” long. They are non-
aggressive normally stinging only to protect the nest. However, bumblebees can sting
repeatedly.

Control: If control is necessary it can be done through habitat modification. Bumblebees
like to build their underground nest in bare ground, so plant over bear spots to discourage
nesting. Otherwise any insecticide labeled for controlling bees should be effective.

                              Carpenter bees, Xylocopa virginica, are considered pests
because of the damage they can do to wood. They’re 3/4” – 1” long, and are sometimes
confused with bumblebees because of their size. However, unlike bumblebees which have
hairy, black and yellow bodies, carpenter bees have a shiny, black abdomen with few hairs.
Male carpenter bees are further recognizable by a cream colored mark on their faces.

Carpenter bees are solitary bees. The female bee bores 6” – 10” deep holes into wood and
packs them with pollen. She lays an egg and then seals the chamber, called a gallery, with
chewed wood pulp. There can be 6 – 7 galleries per tunnel with a single egg in each one.
The larvae will feed on the pollen until they emerge as adult bees 5 – 7 weeks later.
Carpenter bees over winter in protected sites, sometimes back in the tunnels they hatched
from. Carpenter bees sometimes reuse previously dug tunnels annually.

The first signs indicating the presence of carpenter bees are hovering males which protect
the nests and the presence of wood shavings left by the females boring. Although males
hover threateningly to protect the nest, they can not sting.

Carpenter bees’ tunneling is destructive to wood structures and the holes can also attract
wood peckers who peck to eat the larvae. The holes can also provide entry for other insects
and wood destroying fungi to get into the walls.

Control: Carpenter bees can be controlled with carbaryl (Sevin™) applied directly into the
tunnel. If the bees are in the tunnel treat it with insecticide and seal it immediately with
wood putty or caulking compound. If there are no bees present when treated wait a couple
of days and then seal it. Male bees can be treated effectively by just swatting them since
they cannot sting.

Longterm control of carpenter bees can be obtained with a sound wood finish. Paint is
considered the best and preservatives containing metallic salts can also be effective.

                      Orchard Mason Bees, Osmia lignaria ssp., is another type of solitary
bee that nests in wood holes, but with very distinct differences from carpenter bees. Orchard
mason bees take up residence in existing holes of trees or walls left by woodpeckers and
other insects instead of boring their own; therefore they cause no damage to wood. They are
about one-inch long with a blue-green metallic color. Orchard bees are also major
pollinators of spring fruit trees, flowers and vegetables but they do not produce honey.

Orchard mason bees are so desirable as pollinators that some growers construct nest boxes
made of numerous holes drilled into wood blocks to encourage them to nest.

Adults hatch in the early spring and mate. The female then begins collecting pollen and
nectar, which she forms into a ball that she packs into the hole. She lays an egg on the ball
of nectar and pollen and then seals off the area to form a cell. Orchard mason bees create 5 -
10 cells per nesting tube. The reproduction season lasts 4 - 6 weeks and then the adults die.
The eggs mature into adults and lay dormant until they hatch out the following spring.

Control: These bees are non-aggressive and people can get very close without fear of being
stung. Control really should be avoided unless absolutely necessary because they are
beneficial pollinators and not pest to people.

Ground Dwelling Bees, also known as digger bees
or digger wasps, are several groups of solitary bees which nest in holes dug in the ground.
They can range from 1/2" – 3/4" long and be a variety of colors such as blue, green, copper or
metallic red. This group is distinguishable by the numerous holes they leave in the ground
during the spring. The aggregation of holes is called a colony although each individual
female digs a hole in which she lays her eggs. These bees emerge in March and April and
reproduce from March to May. During the night the females dig burrows at least 6” deep.
During the day she collects pollen and nectar which she forms into a ball and stuffs into the
burrow. She then lays an egg on the ball and the larvae will feed on the nectar and pollen
until the adult bees emerge again the following March and April.

Ground bees are excellent pollinators and some prey on other insects. They are non-
aggressive and very rarely sting. Because of their non-aggressive nature they won’t swarm
like social bees if they do sting. However their numerous burrows are unattractive in the
lawn and their hovering above the ground can be intimidating. Though their holes are
unattractive in a lawn or landscape, their burrowing actually helps to aerate the ground and
doesn’t damage plants or grass.

Control: If possible avoid doing any activity in their nesting area during the mating season.
Ground dwelling bees like to nest in bare dry spots with sparse vegetation. Heavily watering
their nesting site and planting over bare spots can discourage them from nesting. If chemical
control becomes necessary treating the area with liquid Sevin should be sufficient.

The insects we all know commonly as bees are in the order Hymenoptera which is
composed of 105,000 species worldwide, 16,300 of which are found in North America.
They are active pollinators, predators and parasites with only a small percentage actually
being pests. They are largely beneficial and non-threatening to humans. By learning to
recognize the different species and their particular characteristics we humans could alleviate
some of our fears, learn to use control methods more appropriately and safely, and preserve
the lives of some very beneficial insects.

References:

Photos courtesy of UGA. at www.bugwood.org

Hey Bug Doctor! , Howell, Jim; UGA Press 2006

Bee Conservation in the Southeast , Delaplane, Keith S.; UGA CES 1998

Bees in Turf , Bambara, S., et.al.; NC State University CES 2001

How to Raise and Manage Orchard Mason Bees for the Home Garden, Bambara, Stephen;
NC State University CES 2001

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