May, 1998

Bee Tidings is a cooperative publication of the University of Nebraska Cooperative Extension and the Nebraska Honey Producer's Association. The newsletter announces events of interest to beekeepers, provides timely advice, and summarizes current research that beekeepers can use. A newsletter subscription includes membership in the Nebraska Honey Producer's Association (NHPA).


In this Issue:

Value-Added Beekeeping Products Workshop

Adding value to beekeeping products will be the subject of a workshop Saturday, June 27, at the Agricultural Research and Development Center near Mead. The workshop will focus on the production of high-quality creamed honey products, but will also include presentations on mead production, honey jellies and jams, and honey candy.

Value-added products provide an opportunity to enhance producer income. They make wonderful gifts, and they bear the unique signature of the craftsman who produces them. Registration is $10 per person and includes lunch, refreshments, and a literature packet. Preregistration is required by June 20. Click HERE for registration form.

Registration will begin at 8 a.m. The program will run from 8:30 to 4:00 p.m. While the program features invited presentations, there will be ample opportunity to visit informally with the presenters about specific problems and procedures. A copy of the program and map to the facility will be sent to all registrants. This program is jointly sponsored by the University of Nebraska Department of Entomology and the Iowa Honey Producer's Association.

Midwest Master Beekeeping Workshop and Queen Rearing Course

The Midwest Master Beekeeping Workshop and Queen Rearing Course are jointly sponsored by the University of Nebraska and the University of Minnesota. This year they will be held on the St. Paul campus of the University of Minnesota from July 23-25.

Master Beekeeping Workshop

The Master Beekeeping Workshop is for experienced beekeepers. The goal of the program is to train participants:

  1. to be successful in their beekeeping,
  2. to share their knowledge about the importance and wonder of honey bees with the public, and
  3. to help new beekeepers.

Mornings will be spent in the classroom where an excellent group of speakers from the Midwest will talk on topics ranging from bee biology to management. In the afternoons, many hands-on workshops will be offered, including disease and mite detection, honey and wax processing, and observation of bee behaviors. Each day, participants will work as teams to solve problems faced by beekeepers. Participants can earn their Master Beekeeper pin and recognition by completing service credit units in the year following the workshop. Enrollment is limited to 70 people, so register early.

Queen Rearing Course

The Queen Rearing Course also will be July 23-25. People who enroll in this course also will participate in the Master Beekeeping Workshop on the morning of July 23 and all day July 25. The afternoon of July 23 and all day July 24 participants will be in a separate classroom learning how to raise queen bees. Classroom topics include queen and drone mating biology, breeding, and record keeping. Hands-on activities will include all the steps involved in queen rearing. Participants can expect to gain the knowledge and experience needed to begin raising honey bee queens. Enrollment in this course is limited to 20 people.

The fee for either course is $95, which includes a workbook, cap, four meals and refreshments. If you would like registration materials, or further information, contact:

Marla Spivak or Gary Reuter
Department of Entomology
219 Hodson Hall
University of Minnesota
St. Paul, MN 55108
(612) 624-6740
spiva001@maroon.tc.umn.edu
reute002@maroon.tc.umn.edu

1999 4-H Essay Contest

The American Beekeeping Federation sponsors an annual Essay Contest for 4-H youth. This year's essay will create a lesson plan and activity sheet to teach third grade school students about bees and beekeeping. The lesson plan should cover the roles of the three castes of honey bees in the colony and one other aspect of bees and beekeeping. The activity sheet can be in the form of a crossword puzzle, a connect the dots puzzle, a word-search puzzle, a drawing on which students label selected items, or any other activity to reinforce the lesson plan message. The activity sheet must be the entrant's original work, and it must be suitable for photocopying. The sponsor will make the activity sheets available to teachers on request.

The contest is open to active 4-H members who have not previously placed first, second or third at the national level. Entries should be typewritten, double-spaced, and printed on one side of each sheet. The length should be 750-1,000 words, plus the activity sheet. All factual statements must be referenced with bibliographical-style endnotes. A brief biographical sketch of the writer should be submitted with the essay and include date of birth, gender, mailing address, and telephone number.

Cash awards of $250, $100, and $50 will be given for the first three places. Each state winner will be awarded a book about honey bees, beekeeping, or honey. Essays should be mailed to Dr. Ackland Jones, State Coordinator, 4-H Essay Contest, Department of Entomology, University of Nebraska, 202 PI Building, Lincoln, NE 68583-0816. Entries should be submitted no later than January 15, 1999. State winners will be announced by March 1 and national winners will be announced by May 1, 1999. Further details are available on the Internet at the sponsor's web site: http://www.abfnet.org/.

Protecting Bee Pollinators from Pesticides

Honey bees are valuable pollinators of crops and wild plants. Without pollinator services, crops would yield less, and wild plants would produce few seeds. (Photo courtesy of Gene Killion.)

Bees are valuable pollinators of 95 crops grown in the United States with a farm value of approximately $10 billion. Bee visits are as vital as soil fertility, irrigation, and pest control in the production of crops requiring bee pollination. In addition to pollinating crops, bees are valuable pollinators of many wild plants that provide food and cover to wildlife, contribute to soil fertility and erosion control, and add beauty to our landscapes. Honey bees also contribute to our agricultural economy by producing $200 million of honey annually. While the honey crop is important to beekeepers, it is a small sum compared to the value of the crops which benefit from bee pollination.

Bees feed exclusively on nectar and pollen and can be distinguished from other insects by the presence of branched body hairs on their thorax and abdomen. There are approximately 3,500 species of bees in North America. Most bee species are solitary and nest in the ground or in cavities such as hollow plant stems. Unmanaged bee species can be locally abundant if suitable nesting habitat and forage are available; however, their abundance is reduced by intensive agriculture and urban development. Bee species managed for pollination in the Midwest include bumble bees (used in greenhouses to pollinate cucumbers and tomatoes), orchard mason bees (tree fruits), leafcutter bees (alfalfa seed production), and honey bees (a variety of crops).

Honey bees are the most important pollinator in the Midwest because they:

  1. are easily managed,
  2. can be transported,
  3. can be managed for income from both honey production and pollination services,
  4. maintain large populations throughout the growing season, and
  5. visit and pollinate many plant species.

Recently introduced parasitic bee mites (varroa and tracheal) have reduced the number of wild honey bee colonies. Likewise, bee mites have caused extensive losses of beekeeper-managed colonies. (For more information on bee mites, see Managing Varroa in the Midwest, NebGuide G92-1302-A).

Pesticide labels carry specific statements to protect bees and should be carefully read prior to application.

Factors in Pollinator Protection Strategies

Plant Growth Stage.

Almost all cases of bee poisoning result from insecticides being applied to blooming crops or being allowed to drift onto blooming crops or weeds. Insecticide applications usually are not recommended for blooming crops. When the label permits insecticide application to blooming crops, growers and applicators need to communicate with beekeepers and exercise all reasonable measures to lower the risk to bees.

Relative Toxicity of the Chemical.

Pesticides vary in their toxicity to honey bees. Most fungicides and herbicides are not toxic to honey bees and can be used without endangering them. Some insecticides and miticides are not hazardous to bees and can be applied without risks of bee injury. For example, Bacillus thuringiensis (sold under the brand names: Dipel, MVP, Thuricide, Biobit, etc.) is a biological insecticide that is not toxic to bees. Insecticides that are moderately toxic to bees can be applied when bees are not actively foraging. Synthetic pyrethroid insecticides will kill bees present during application, but then, many of them exhibit repellency to bees. Bee losses caused by pyrethroids are usually moderate. Insecticides that are highly toxic to honey bees cannot be applied to blooming crops when bees are present without causing serious injury.

Choice of Formulation.

Different formulations of the same insecticide often vary considerably in their toxicity to bees. Granular insecticides generally are not hazardous to honey bees. Dust formulations (seldom used today on commercial field crops) are typically more hazardous than emulsifiable concentrates, because they adhere to the bee's body hairs and are carried back to the beehive. Wettable powder and flowable formulations essentially dry to a dust-like form and also can be carried to the hive by foragers. Likewise, microencapsulated insecticides can be collected by foragers along with pollen and carried back to the beehive. Honey bee exposure to insecticides that kill foraging bees in the field reduces honey production, but colonies recover as young bees emerge. Exposure to dust, wettable powder, flowable and microencapsulated insecticide formulations can cause severe losses of both foraging bees and hive bees. In the worst cases, toxins may remain active in the hive for several months and prevent colonies from recovering from the injury.

Residual Action.

Residual activity of an insecticide is an important factor in determining its safety to pollinators. An insecticide which degrades within a few hours can generally be applied with minimal risk when bees are not actively foraging. Applying insecticides with extended residual activity - more than 8 hours - when bees are not actively foraging will not prevent bee injury if bees visit the crop during the period of residual activity. Insecticides with extended residual activity merit extra precaution to prevent bee exposure. Penncap-M (microencapsulated methyl parathion) with a residual period of 8 days and Furadan F (flowable carbofuran) with a residual of 14 days fall into this classification.

When the target crop is not blooming or is unattractive to bees, insecticide drift can cause significant bee poisoning if drift reaches adjacent flowering crops or weeds. In general, sprays should not be applied if wind speed exceeds 10 mph and favors drift toward flowering crops or weeds. While pesticides should not be sprayed over colonies or allowed to drift onto them, drift over colonies rarely causes bee poisoning. When evaluating potential drift hazards, focus on drift to blooming plants.

Temperature.

Temperature can have a substantial effect on the bee poisoning hazard. If temperatures after treatment are unusually low, insecticide residues can remain toxic to bees for much longer than if normal temperatures prevail. Conversely, if high temperatures occur during late evening or early morning, bees may forage during these times.

Distance from Treated Fields.

Most honey bees forage within 1-2 miles of their colony, but they can go up to 5 miles when nectar and pollen are scarce near the hive.

Honey bee mortality usually decreases as the distance of colonies from treated fields increases. (The most severely damaged colonies are usually those closest to the application site.) Most foraging activity occurs within a one to two mile radius of the hive; however, during periods of pollen or nectar shortage, bees forage at greater distances, and colonies up to five miles from the treated area can be injured.


Time of Application.

Timing of application is related to all the previously mentioned factors. Again, the most critical factor is to control pests prior to bloom or after bloom is complete, when possible. Evening application of a short-residual insecticide can greatly reduce the potential for bee injury.

Lack of Communication.

Reducing insecticide injury to honey bees requires communication and cooperation between beekeepers, farmers and applicators. It is important that beekeepers understand cropping and pest management practices used by farmers near their apiaries. Likewise, insecticide applicators should be aware of apiary locations, have a basic understanding of honey bee behavior and learn which materials and application practices are hazardous to bees. It is unlikely that all bee poisonings can be avoided entirely; however, in most cases, bee losses can be prevented by knowing the hazards and maintaining effective communication.

How Applicators Can Reduce Risks of Honey Bee Injury

Do not treat fields in bloom.

Be especially careful when treating crops such as alfalfa, sunflowers, and canola that are highly attractive to bees. Insecticide labels carry warning statements about application during bloom. Always read and follow the label.

Examine fields and field margins before spraying to determine if bees are foraging on flowering weeds.

Milkweed, smartweed and dandelion are examples of common weeds that are highly attractive to honey bees. Where feasible, eliminate blooming weeds by mowing or tillage prior to insecticide application. While bright and colorful flowers are highly attractive to bees, some plants with inconspicuous blossoms also are visited. Examples of these plants include dock, lambsquarter, and ragweed. When examining areas for blooming plants, consider all blooming plants. It is also important to be aware that many plants only offer pollen and nectar for a few hours each day, and that fields should be scouted for bees at the same time of day as the anticipated insecticide application.

Choose short residual products and low hazard formulations.

If insecticides must be applied during the flowering period to save a crop, select the least hazardous option. Notify local beekeepers as far in advance as possible. Avoid spray drift. Give careful attention to the position of blooming crops and weeds relative to wind speed and direction. Changing spray nozzles or reducing pressure can increase droplet size and reduce spray drift.

Apply insecticides when bees are not foraging.

Some insecticides can be applied in late evening or early morning (i.e. from 8 p.m. to 6 a.m.) with relative safety. In the case of corn, bees collect pollen from tassels in the early morning and are not present in the afternoon or evening hours. Short residual materials applied from late afternoon until midnight do not pose a bee hazard in corn fields if blooming weeds are not present.

Adjust spray programs in relation to weather conditions.

Reconsider the timing of insecticide application if unusually low temperatures are expected that night. Cool temperatures can delay the degradation process, and cause residues to remain toxic to bees the next day. Cease applications when temperatures rise and bees re-enter the field in early morning.

Contact local beekeepers and obtain locations of bee yards.

Nebraska state law requires that apiaries be clearly identified with name, address and phone number of the beekeeper. Identification may appear on one or more colonies, or a separate sign may be posted in the apiary. The Nebraska Department of Agriculture (402-471-2394) maintains a list of apiary locations and can provide assistance in identifying the owner of an apiary. If colonies are present in an area that will be sprayed with a bee-toxic insecticide, contact beekeepers in time for them to protect or move the colonies. Many pesticide applications pose minimal risk to bees, and beekeepers may choose to accept some risk rather than move colonies.

Read the pesticide label.

Carefully follow listed precautions with regard to bee safety.

Providing forage in uncultivated areas will benefit both wild and managed bees. Many other beneficial insects, such as parasitic wasps, will also benefit from the availability of nectar and cover.

Maintain bee forage areas.

Intensive agriculture often increases bee dependence on cultivated crops for forage. Encouraging bee forage plants in wild or uncultivated areas will reduce bee dependence on crop plants that may require pesticide treatments. Plants recommended for uncultivated areas include sweet clover, white Dutch clover, alfalfa, purple vetch, birdsfoot trefoil, and partridge pea. Most trees and shrubs are beneficial to bees. The most attractive include linden, black locust, honey locust, Russian olive, wild plums, elderberries, red maples, willows, and honeysuckle. Game management and soil conservationists usually are eager to cooperate in establishing plantings that benefit bees because these areas also conserve soil and provide valuable habitat for plant and wildlife conservation programs.

Steps Beekeepers Can Take to Protect Their Colonies

Choose low hazard apiary locations.

Do not locate bees adjacent to crops that are likely to be sprayed with an insecticide.

Know the risks.

Many crop pests can be controlled without endangering bees. Attend crop pest management training sessions to stay informed about crop pests and control measures used by growers and applicators. These sessions also provide an opportunity to establish communication links with growers and applicators.

Maintain positive working relationships with applicators.

Risk management decisions can best be made when both parties understand each other's needs. Establish a communication link prior to the spray season rather than during peak activity when both parties are busy.

Register apiaries and post identification.

Register your apiaries with the State Department of Agriculture, Agricultural Stabilization and Conservation Service or any other agency that assists applicators seeking to contact beekeepers. Post your name, address and telephone number in a conspicuous place in your apiaries.

Be prepared to protect colonies if necessary.

Frequently, pests can be controlled without putting honey bees at risks. If pest control measures are necessary but carry unacceptable risks, know the options for protecting colonies and be prepared to implement them. These options include:

  1. Briefly confine bees to their hive with wet cloth when products with short residual activity are applied. This measure is only feasible if a small number of colonies are involved and if the confinement period is brief and early in the morning. Caution! This measure can result in colony injury due to overheating and should be used with care.
  2. Disrupt foraging activity temporarily when short residual materials are applied by removing colony covers and offsetting boxes so as to increase colony exposure. This will result in a temporary reduction in foraging. Most bees will remain in the hive to protect their stores and maintain nest conditions in the exposed nest. After a few hours to one day, colonies will adjust to the change and resume foraging. This method is safer than confining colonies but is not recommended if bees are located in or adjacent to fields that will be treated.
  3. Move bees to another location at least four miles from the treated area when highly toxic products with extended residual activity are applied to blooming crops. Moving populous colonies during hot weather can result in considerable bee mortality and should be avoided if possible. Moves should be made in the early morning hours when temperatures are cool and the bees are least active.

Provide educational resources to growers and applicators.

There are many ways to alleviate bee poisoning. Often, severe losses can be avoided by relatively simple modifications of pest control programs. Talk with growers and applicators about how to reduce bee injury, and provide them with reference materials on protecting bees when you establish apiaries in their areas.

Honey Bee Activity in Field Crops and Rangeland

Wheat and Small Grains.

Bees are not likely to be present in wheat or other small grains unless flowering weeds, such as wild mustards, are present.

Corn.

A 1995 study found that corn's contribution to the pollen loads of honey bees was relatively small at five study sites in intensive corn production areas of Nebraska. During the pollen shed period, corn pollen constituted 0 to 9% of the pollen recovered from colonies with an average of 2.1% for all sites. Bees typically collect corn pollen in the early morning hours when pollen is shed and should not be present in large numbers after 1 p.m.; however, products with extended residual activity that are applied in the afternoon or evening can be picked up by foragers the next day and cause serious injury to colonies. While bees collect some corn pollen, other plants, including blooming weeds in field margins and irrigation ditches, provide most of the pollen and nectar that honey bees collect during corn pollination. Mowing blooming weeds in field margins and ditches prior to applying an insecticide will substantially reduce the risk of honey bee injury. However, it is best to remove bees from the area before treating pollinating corn with Penncap-M (encapsulated methyl parathion), Furadan F (flowable carbofuran), or any other product with extended residual activity since bees collect some corn pollen. Moving bees in mid-summer is expensive, labor intensive and may result in bee mortality due to overheating during confinement. Beekeepers need to evaluate their risk before moving bees. Good communication with growers and applicators is essential.

Grain Sorghum.

Bees forage in sorghum fields when the grain heads are shedding pollen. Sorghum is not a preferred source of pollen, but bees may be present in large numbers if other sources are not available. A 1995 Nebraska study found that sorghum's contribution to the pollen loads of honey bees was highly variable at the five sites examined. Sorghum contribution to pollen loads ranged from 34% to less than 1% in the study. The variability probably reflects the availability of competing bloom. Most bee activity on sorghum flowers will occur early in the morning, especially when dew is present. Dew facilitates collection of the dry, powdery pollen of sorghum and other wind-pollinated plants.

Sugar Beets.

Bees will not be present unless flowering weeds are in the field.

Mustards in an alfalfa meadow. Even though the crop (alfalfa) is not in bloom, severe injury can occur if blooming weeds are present.

Alfalfa.

Alfalfa blossoms are among the most preferred by honey bees and they are likely to be present throughout flowering. Bees are necessary to pollinate this crop when grown for seed. Bees also will forage on weeds, such as dandelions and mustards, in pre-bloom alfalfa, particularly in mature or thin stands. Blooming alfalfa should always be mowed prior to spraying for alfalfa weevil control. Mowing protects pollinators and improves the efficiency of control measures.

Sweet Clover.

Sweet clover is probably the most attractive honey bee forage plant, whether it is grown to provide cover or hay, to improve the soil, or for seed. The plant is common along roadways, in wildlife habitat areas, and in pastures and rangeland. Honey bees will be active in sweet clover throughout bloom and are required if the crop is grown for seed.

Soybeans.

Soybean flowers are attractive to foraging bees and, in some areas, may be a primary source of nectar. Pre- and post-bloom applications of insecticides are unlikely to result in bee poisoning. Care should be taken to avoid spraying blooming weeds if present in the field or field margins.

Pastures and Rangeland.

Some honey bee colonies are located in rangeland areas, usually along shelter belts. Pastures will attract foraging honey bees when flowering plants are present. Pastures with legumes, such as sweet clover, alfalfa, white Dutch clover and vetch are highly attractive to bees. Bees usually will be present throughout the day when blooming legumes are present.

Vetch.

Bees are essential to pollinate this crop when grown for seed. Bees are likely to be present throughout flowering.

Sunflowers.

Sunflowers are very attractive to honey bees. Expect them to be present throughout the bloom period at all hours of the day. Honey bees are necessary to pollinate many lines of sunflowers.

Field (Dry) Beans.

Honey bees visit dry beans sparingly; however, when large numbers of honey bee colonies are in the area, bees can be abundant in dry bean fields. Scout bean fields for bees if bloom is present.

Relative Toxicities of Selected Insecticides and Miticides to Honey Bees

Length of residual toxic effects is in hours or days.

Do not apply to blooming crops or weeds.
Cygon (dimethoate) 3 days
Furadan F (carbofuran) 7-14 days
Guthion (azinphos-methyl) 2.5 days
Lorsban EC (chlorpyrifos) 4-6 days
malathion ULV (8 fl oz/acre or more) 5.5 days
Orthene (acephate) 3 days
Penncap-M (methyl parathion) 5-8 days
Sevin WP (carbaryl) 3-7 days
Temik G (aldicarb) apply at least 4 weeks before bloom
Apply only during late evening.
Dibrom EC (naled) 16 hours
malathion EC 2-6 hours
Pydrin (fenvalerate) 6 hours
Sevin XLR (carbaryl) 8 hours + (1.5 lb. per acre or less)
Thimet EC (phorate) 5 hours
Thiodan (endosulfan) 8 hours
Apply during late evening or early morning.
Ambush (permethrin) 1-2 days, safened by repellency under arid conditions
Ammo (cypermethrin) less than 2 hours
Asana (esfenvalerate) 1 day, safened by repellency under arid conditions
Dyfonate EC (fonofos) 3 hours
Lannate LS (methomyl) 2 hours +
Metasystox-R (oxydemetonmethyl) less than 2 hours
methoxychlor (DMDT, Marlate) 2 hours
Pounce (permethrin) 1-2 days, safened by repellency under arid conditions
Systox (demeton) less than 2 hours
Can be applied at any time with reasonable safety to bees.
Comite (propargite)
Dimilin (diflubenzuron)
Dipel (Bacillus thuringiensis)
Dyfonate G (fonofos)
Furadan G (carbofuran)
Kelthane (dicofol)
margosan (neem oil)
nicotine sulfate
Plictran (cyhexatin)

Information on products not included in this newsletter can be found on the pesticide label.

Subscription Information

Bee Tidings is published jointly by University of Nebraska Cooperative Extension and the Nebraska Honey Producer's Association six times a year. A subscription includes membership to the association. Subscriptions are for one year and begin with the November issue.

To subscribe to Bee Tidings, send a $10 check made out to the University of Nebraska-Lincoln along with your name, address, and phone number to:

Bee Tidings
Box 830918
University of Nebraska-Lincoln
Lincoln, NE 68583-0918

This newsletter was respectfully written by:
Marion D. Ellis
209 Plant Industry, Box 830816
University of Nebraska
Lincoln, NE 68583-0816
Phone: 402-472-8696
Fax: 402-472-4687
Internet address: mellis@unlinfo.unl.edu

Your comments and suggestions about the newsletter are always welcome.