Welcome to the Harpur Lab's Bee Hive.
We are involved in honey bee research and education.

Click here for hardy
Indiana queens and bees

Do you have a swarm to pick up? Find a local swarm catcher here: http://www.in.gov/dnr/entomolo/5755.htm
When bees swarm the queen and most of the hive bees leave after filling up on honey. Bees in a swarm are usually very gentle but leave them alone! With all those bees flying one could get stuck in your hair. The swarm sends out scout bees to find a new cavity to nest in. They usually stay for a few days and then they are off to their new home.

Lab Team

Brock Harpur

Assistant Professor


Krispn Given

Apiculture Specialist




by Greg J. Hunt

General Considerations - Why use honey bees?

Many crops are dependent on pollination by bees for adequate fruit set. North America has over 3,000 species of wild bees. Some of these species are much more efficent than honey bees on a per-bee basis for pollinating specific plants. But almost all of the wild bees are solitary. A single female makes a nest, forages and cares for the brood, so solitary bees do not have colonies. Honey bees are social - they have a colony containing one queen that lays all the eggs and with tens of thousands of worker bees to do the foraging. Many of the wild bees only visit specific kinds of plants, or are only active for part of the season. The orchard mason bee is useful because it is active during the spring and is an efficient pollinator of apples. Mason bees can be encouraged to nest in plastic straws, or holes drilled in wood. Their progeny return to the same orchard the next year. Bumble bees are important because they are large, active foragers and are also social - living in small colonies that are active throught the season. Honey bee colonies also are active throughout the growing season. Worker honey bees will visit any flowers that provide good amounts of nectar or pollen, the two resources bees need for energy and protein. The main advantage of using honey bees is that we can manage colonies with tens of thousands of bees, to serve as mobile pollination units.

What's a good pollinating hive?

Bee hives consist of several boxes - one or two brood chambers and several smaller boxes, called supers. A tall hive usually is a strong hive (having many bees), which makes it good for pollination. But an unscrupulous beekeeper could put empty boxes on the hive to make it look strong. If it is a strong hive, it should have lots of bees coming and going from the entrance on a warm day. If you have the lid off, there should be many bees filling at least one or two large brood chambers, with a carpet of bees covering the tops of the frames. A good pollinating unit will have at least one deep brood chamber full of bees, brood and eggs (indicating that they have a queen).

Moving hives

Bee hives are usually moved after sunset to avoid losing foraging bees. Beekeepers that move only a few hives usually just screen off the entrances and load the hives individually on a truck. Larger beekeepers usually move hives on pallets with four hives per pallet. The grower should expect the hives to come at night and make arrangements with the beekeeper on where the hives will be placed in the orchard or the edges of the field.

Timing the move

The importance of timing depends on what flowers are competing for the attention of the bees. One thing to consider is the attractiveness of your crop as a nectar source. Bees are very good at locating the sweetest nectar in the area and often this comes from weeds in the surrounding fields. Bees like to forage within 300 feet of the hive but will travel two miles or more for a good nectar source. Ideally, it is best to have the bees moved into the crop just as flowering has started in earnest, so that the bees do not get used to foraging on the nearby weeds. If they are moved in too soon, there may not be enough of the crop blooming to effectively compete with the weeds.

Consider having a pollination contract

When contracting for pollination, it is important that the beekeeper and grower discuss details. Which pesticides will be used, if any, while the bees are present? Bees are extremely sensitive to sprays on flowers. It is possible for a beekeeper to lose all 300 of his colonies in one week to pesticide poisoning during pollination. The beekeeper should have access to the colonies at all times to inspect them and make sure they still have queens and are healthy. The beekeeper and grower should be aware of which pesticides are most toxic to bees. All of these points should be decided ahead of time. It is best to sign a formal contract with the beekeeper. This protects both the grower and the beekeeper. A sample pollination contract appears at the end of this document that can be modified to fit your needs.

Pesticide Toxicity

The acutely toxic effects of pesticides to bees are measured by experiments in which the test compound is administered to bees as a contact pesticide in a controlled way. The following short table indicates how pesticides are rated based on their LD50's (the concentration in microgram/bee needed to kill 50% of the test bees).

Classification of toxicity based on LD50's (µg/bee)
greater than 100 virtually non-toxic
11-100 slightly toxic
2.0-10.99 moderately toxic
less than 2.0 highly toxic

Residue Exposure

Some pesticides are very toxic to bees but can still be applied to the blossoms in the evening because they rapidly decay to less toxic compounds. The residual activity of pesticides is often expressed as an RT25 value. This is the time that needs to pass for the pesticide to degrade enough that bee mortality is reduced to 25% of the initial mortality of the freshly applied product. This test is done by spraying the pesticide on alfalfa leaves and keeping the leaves in a cage with bees at 75°F. But cooler temperatures can dramatically increase the time needed for residues to become non-toxic to bees. Be careful when the weather is cool.

For more on bees and pollination, including a list of pesticides and their proper application, view and download the Purdue Entomology Extension E-Series Publication:
E-216-W Using Honeybees in Pollination.



The Problem with Mites

Varroa currently is the most serious problem encountered when keeping bees. They are large enough to see on the bees and reproduce in the brood cells of the comb. It is best to use some monitoring method to know how many mites are in your hive. Many people use "sticky boards" covered with screen to see how many mites are falling off the bees. To control Varroa mites with chemicals you must use a product that is safe and effective. The mites in our area have become somewhat resistant to Apistan strips, so we will not use it until the mites become susceptible again. Checkmite strips are very effective (at least for now) but can be harmful to developing queens. We recommend keeping these strips in the hive for just two weeks because the active ingredient, coumaphos, is more toxic than the active ingredient in Apistan. Treat with the strips as soon as you can take your honey off (usually about August 1-7 here in Indiana ). Another treatment is Apilife VAR, which uses thymol to kill mites. This needs to be done when the weather is warm enough (70°-90°F). It also helps to have bees that are more resistant to the mites so consider buying bees from queen breeders that are selecting bees for traits that give bees more resistance.

Genetics of Mite Resistance

Despite talk of colony collapse disorder, surveys indicate that Varroa mites are still the single most deadly factor in colony losses. Studies in the US and Mexico pointed to two behavioral traits as important resistance mechanisms. The USDA Baton Rouge Bee Lab found that some bees can detect the mites when they are inside brood cells and they uncap these cells, which disrupts mite reproduction. This has been called Varroa Sensitive Hygiene or VSH. A study in Mexico showed that some bees are better at grooming mites off of themselves and biting the mites. The bees are fighting back and we want to help! We are working with Indiana beekeepers to select for higher mite-grooming behavior in bees adapted to northern winters. We are also collaborating with the Baton Rouge lab and a colleague in Mexico to map the genes that influence these two behaviors.

Honey bee egg in a cell and immature Varroa mites in the cell next to it
(Harry Laidlaw)

Honey bee egg in a cell and immature
Varroa mites in the cell next to it (Harry Laidlaw)

Treating for tracheal mites in two ways

  1. Menthol crystals - use one 50 gm packet per colony. Best time to treat is early spring, but only when it is at least 70°F outside. Place packet on top bars above the cluster of bees.
  2. Crisco patties - mix one pound vegetable shortening with two pounds sugar. Make a small patty between wax paper (about the size of your hand) and leave it in the hive continuously. This should reduce tracheal mite populations by half.

    Many bees are resistant to tracheal mites and may not need any treatment but it is difficult to see the mites and diagnose resistance. We do not treat for tracheal mites in our hives. Rather, we re-queen if the bees are susceptible.

For more on mites, view and download the Purdue Entomology Extension E-Series Publication:
E-201 Parasitic Mites of Honey Bees.

Submission of Samples for Diagnosis

Samples of Adult Honey Bees
  • Send at least 100 bees and if possible, select bees that are dying or that died recently. Decayed bees are not satisfactory for examination.
  • Bees should be placed in 70% ethyl or methyl alcohol as soon as possible after collection and carefully packed in leak-proof containers.

Samples of Brood Comb
  • A comb sample should be at least 2 x 2 inches and contain as much of the dead or discolored brood as possible. NO HONEY SHOULD BE PRESENT IN THE SAMPLE .
  • The comb can be sent in a paper bag or loosely wrapped in a paper towel, newspaper, etc. and sent in a heavy cardboard box. AVOID wrappings such as plastic, aluminum foil, waxed paper, tin, glass, etc. because they promote decomposition and the growth of mold.
  • If a comb cannot be sent, the probe used to examine a diseased larva in the cell may contain enough material for tests. The probe can be wrapped in paper and sent to the laboratory in an envelope.

How to Address Samples

  • Send samples to:

    Bee Disease Diagnosis 
    Bee Research Laboratory 
    Bldg. 476 Room 204 
    Beltsville Agricultural Research Center - East 
    Beltsville, MD 20705

  • Include a short description of the problem along with your name, address, phone number or e-mail address.
  • There is no charge for this service.
  • For additional information, contact Bart Smith by phone at (301) 504-8821 or e-mail: smithb@ba.ars.usda.gov

Honey Bee Diseases, Pests and Medications

Disease Signs Treatment Cause Method
Diarrhea (Nosema) Brown spots and streaks on hive box where bees come out. Fumadil-B - Providing good ventilation really helps! A protozoan - living in the bee's gut: Nosema apis If it is a problem, treat package bees in spring with Fumadil in 1:1 sugar syrup. Treat hives with 2:1 sugar syrup in fall. Nosema can be a problem in winter.
American Foulbrood An uneven pattern of brood with lots of empty cells. Some cell cappings may look darkened and sunken. Cells may be partially opened by bees. Larvae die after cell is capped. You might smell something bad. Terramycin - Destroy badly infected frames with scales of dead larvae by burning or discard in sealed trash bags. Bacteria - Paenobacillus larvae (= Bacillus larvae ) Not necessary to treat if there is no problem. Watch for symptoms and treat if needed. Srinkle powdered sugar mixed with Terramycin according to the label instructions (3 treatments, 5 days apart).
Tracheal Mites No obvious symptoms. Mites that are too small to see are inside the breathing tubes of the bees. In winter, infested bees may crawl out of the hive and die. Usually none required - Some people use menthol crystals. A mite - Acarapis woodi No treatment needed. Most bees are resistant to tracheal mites. If your bees die in the winter, purchase queens from a different supplier.
Chalkbrood Dead larvae become white or grey cottony "mummies" inside of cells. Mummies may be seen discarded by bees in front of hive. (cool weather problem) Usually none required - Feed sugar syrup, add more brood or requeen. A fungus - Ascosphaera apis No drug needed. Chalkbrood often clears up when weather improves or after a new queen is introduced to the hive.
Varroa Mites Look for Varroa mites in capped cells (especially drone cells) or on adult bees. In bad infestations, you see an uneven pattern of brood with some dead brood. Some bees may have deformed wings. Eventually results in death of the colony, especially early winter kills. Apistan strips - (fluvalinate), Checkmite+ strips (coumaphos), Apilife VAR tablets (contains thymol oil) A mite - Varroa destructor ( = V. jacobsoni ) Check for Varroa spring and summer with sticky boards. Many Varroa mites are now resistant to Apistan! Checkmite is very effective but is more toxic and could harm developing queens. Apilife VAR is less toxic but more labor intensive. This is the one bee disease that must be controlled!
Wax Moths Webbing in comb. Wax moth larvae bore right through bee brood and comb, leaving lines of dead brood and webbing. Can destroy good comb! This is a problem of weak or dead hives and stored comb. PDB moth crystals (Paradichlorobenzene) are used in stored equipment only. Not moth balls! Bees usually control moths in colonies. Remove dead colonies. Greater Wax Moth - Galleria mellonella is especially attracted to combs containing brood and pollen. Stack hive bodies or supers and put a piece of newspaper on top. Place 1/3 cup of PDB moth crystals on paper above every fourth box. Renew as crystals evaporate. Or kill moths by putting boxes in freezer.
Viral diseases are also important and increase with Varroa infestations but there is no known effective treatment. 
Follow all label instructions.

Click here for a printable version of the Honey Bee Diseases, Pests and Medications.