APIS Volume 11, Number 2, February 1993

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• In Search of a Management Plan for Varroa, Tracheal Mites and African Bees

IN SEARCH OF A MANAGEMENT PLAN FOR VARROA, TRACHEAL MITES AND AFRICAN BEES

Dr. Keith Delaplane, Georgia Extension Beekeeping Specialist, said at the recent meeting of the American Beekeeping Federation in Kansas City that 1988 was a pivotal year in U.S. beekeeping. It was the first time a pesticide had been labeled for use inside a living honey bee hive. This event has led to the realization by regulators and beekeepers alike that eradication of tracheal mites, Varroa mites and African honey bees is not possible. That leaves the beekeeping industry no alternative but to manage the populations of these organisms so they remain at low levels and cause as few problems as possible.

With all of the above in mind, the Apiary Inspectors of America (AIA) has drafted a model pest management plan. No regulatory or management plan is perfect, according to Mr. Marion Ellis, Nebraska State Apiarist and one of the drafters of the model plan. The perfect bee law, he said, also at the Kansas City meeting, would have only two articles:

1. All diseased colonies be burned
2. Regulations would only be enforced on competitors.

Although there are problems with any bee law, Mr. Ellis concluded, he urged not to trade good for perfect by discarding all regulations.

The details of the model pest management plan are still under discussion by various groups. In order to widen the dialogue, I have decided to reprint here what was written about each of the above problems and specific recommendations to deal with each. Comments or questions can be mailed to me and I will transmit them to the authors.

Honey Bee Tracheal Mite (HBTM) (Acarapis woodi): Beekeepers in the U.S. have had to contend with tracheal mite and an array of differing regulations since 1984. The pest has been devastating primarily to northern beekeepers. It is no longer regulated. A significant development is the emergence of resistant bee populations (many susceptible populations appear to have been eliminated), especially the "Buckfast" bee. Two products have been labeled for control and mite populations can also be suppressed by management (making splits and requeening) and by locating bees in favorable areas for nectar secretion and overwintering. The ideal pest management strategy is to employ all of the above (genetic resistance, chemicals, and management).

Specific management recommendations are:

1. Monitor the level of HBTM infestation periodically via microscopic examination.
2. Select for resistant stock by rearing queens from hives exhibiting vigor and low level HBTM infestation in apiaries which are suffering losses due to HBTM infestation.
3. If treatment is warranted, use only registered pesticides according to the label directions.
4. Treat colonies early in the spring and during the late summer/fall season prior to the production of "winter bees." Late fall treatment after brood rearing has ceased does little to minimize winter mortality. One possible explanation is that the honey bees have already had their lives shortened by parasitism and possible viral transmission via the mite's feeding behavior.
5. Assess the merit in treating weak, heavily infested colonies. Elimination of these hives may prove beneficial in the long term. Perpetuating susceptible lines is one result of relying on pesticide usage.
6. If pesticide treatment is the method of choice for managing HBTM populations, consider rotating pesticide treatments. Chemical rotation will slow the development of mite resistance.
7. Get back to beekeeping basics such as regular requeening of colonies and feeding fumagillin for nosema control. Eliminate or bolster weak hives with young bees and capped brood from strong, healthy colonies.

Varroa Mite (Varroa jacobsoni): Since detection in 1987, Varroa has quickly spread throughout the U.S. Varroa mite management recommendations and various state rules are based on nuisance abatement rather than eradication. They are intended to reduce treatment frequency, cost and "invasion potential" (re-infestation) by mites after nearby colonies collapse. They establish an action threshold which recommends that beekeepers treat when mites' levels are found to exceed the threshold.

Beekeepers are encouraged to monitor their colonies and treat on an annual basis (more frequently in some areas) when Varroa is present. Treatment should be done during the fall or early spring when brood rearing is minimal. An important aspect of Varroa control is for all beekeepers in an infested area to treat at the same time of year to reduce re-infestation from untreated colonies.

Currently, two pesticides are registered for Varroa control. The beekeeping industry must avoid the treadmill of pesticide dependence. It should promote methods to develop pesticide use specifically and selectively and with particular concern for the damage threshold of mites attacked, so that unnecessary treatments are avoided. Varroa has been prevented from causing catastrophic damage, but mite resistance to pesticides is a real problem in other agricultural industries and will be so for beekeeping unless extreme precaution and common sense are followed.

Local and regional mite activity will vary due to climate and geography. Beekeepers are encouraged to actively participate in organizations and seek out regulatory and extension officials for current information on pesticide use. Specific management recommendations are:

1. Sample apiaries during early spring and at regular intervals throughout the brood rearing period via a sampling technique such as the ether roll, alcohol shake or sticky-board detection method.
2. Sample a minimum of 10% of the colonies within the apiary. Concentrate on colonies at the end of rows or from those which appear abnormal.
3. Operations which have Varroa infestations should treat with a labeled pesticide during the fall. A treatment early in spring prior to honey production or interstate movement for pollinating purposes is also recommended. When all crop pollinating colonies are treated prior to movement, the risk of infestation by nearby untreated operations is reduced.
4. Avoid treatment at the colony level. Treatment of the apiary or operation is more effective and easier to track.
5. Keep a log to document the treatment period and pesticide used.
6. Perform a post treatment survey on a small percentage of colonies via the ether roll or alcohol shake method. Post- treatment surveys will identify any problems such as resistance or poor pest control. Avoid pest treatment surveys with the same pesticide used in treating colonies, otherwise, if there is pesticide resistance it will not be evident.
7. Rotate pesticides in order to slow the development of resistance by Varroa to a particular compound.
8. Coordinate treatment periods with beekeepers in the area. This can be accomplished via local, state and regional beekeeping associations. When determining a treatment period, consider the biology of the mite, honey bee, and beekeeping management routine in the area. If possible, avoid treatment when it contradicts biological or management constraints.
9. Varroa infestation should be controlled before large populations build within colonies. Several states have established "action thresholds" or infestation levels which require treatment. Generally speaking, when Varroa mite counts exceed ten mites per ether roll per sample of 250 honey bees, treatment is warranted. Determination of an action threshold based on scientific research should be a priority of the beekeeping industry.
10. Open feeding of sugar syrup and honey is discouraged. Open feeding has never been an efficient or cost effective method of feeding colonies. Generally speaking, it promotes robbing and defensive behavior. Often the strong hives in an area are the ones which gather the feed, while weak hives are robbed out or at best gather little syrup. Open feeding provides the opportunity for the spread of Varroa between apiaries. In addition, open feeding of syrup has caused the death of both cattle and deer when large amounts have been consumed by these animals.
11. It is likely that certain colonies will exhibit some resistance to Varroa. These colonies should be identified and brought to the attention of bee breeders and/or researchers so the industry can work toward a genetic solution to the Varroa problem.

Africanized Honey Bee (AHB): The Africanized honey bee will present both management and public relations challenges to America's beekeepers. It is incumbent on beekeepers, government and the agricultural community to be proactive in projecting a positive image within the community. The Agricultural Extension Service needs to develop a national public relations campaign similar to those developed by the Mexican Department of Agriculture and Texas A&M.; Beekeepers must exercise common sense and operate under a "code of ethics" which precludes nuisance situations. Even under the best scenario, it is inevitable that certain communities will restrict beekeeping in coming years as a reaction to a perceived threat from AHB, or more likely, due to inconsiderate actions on the part of a few beekeepers.

Growers dependent on honey bees for pollination must also work toward projecting a positive image to the public. Growers and beekeepers should establish apiary sites with minimal potential for interaction with the public. Placement of colonies near high traffic areas must be avoided. Hedgerows should planted along roads when necessary to screen the view of colonies and divert the flight path of bees above roads, etc. Growers can also provide water sources for hives while they are in staging areas and in the field as many nuisance problems arise from the bees' need for water.

On October 24-26, 1991, the USDA and NASDA sponsored a workshop in order to develop a Model Honey Bee Certification Plan (see full text in APIS, January 1992). Representatives of the honey bee industry, user groups, regulators and researchers participated in the development of a certification plan that addressed various bee diseases and Africanized bees. At this meeting a consensus was reached with regard to AHB, recognizing the diminishing state resources available for apiary inspection and certification. A philosophy based upon self-help and management practices rather than strict regulations was deemed the only workable approach in addressing AHB. Specific management recommendations are:

1. Colony management for the purpose of stock certification should be consistent with the recommendations developed at the USDA/NASDA workshop.
2. Queens should be purchased or produced from certified stock.
3. Locate colonies of bees away from roads so the bees do not interfere with vehicular or pedestrian traffic.
4. Avoid placing colonies near or on utility (power lines, underground cables, pipelines) right of ways unless permission is granted.
5. Avoid placing colonies near schools, municipal recreation areas (especially swimming facilities), parks, picnic grounds or other locations which may encourage adverse honey bee/public interactions. Areas with water sources or a sugar source from trash cans, soft drink vendors, etc., aren't conducive to positive public reactions.
6. Open air feeding of honey and sugar syrup is not recommended as it promotes defensive behavior by the bees and the spread of diseases or pests.
7. Provide clean water sources in apiaries that do not have natural supplies of water or in areas with residential swimming pools.
8. Locate staging yards away from populated areas even if only a few houses are nearby. Staging yards tend to have defensive colonies.
9. Park trucks loaded with full supers away from areas frequented by people, especially when stopping at a store for a drink, etc. Many bees remain in the supers during honey removal. The best approach is to net honey laden supers.
10. All loads of bees should be netted or screened even when moving at night.
11. Requeen colonies that exhibit consistent defensive behavior.
12. Try to manipulate colonies during optimal weather conditions and advise landowners, especially those with livestock, when major manipulations such as honey harvest are to be performed.

Conclusion: Developing a model beekeeping management plan will require input from beekeepers, growers, researchers, extension educators, and others. A successful pest management plan must be based upon a thorough understanding of the host-pest-disease complex. Apiary management routines vary according to geographic region and climate and pest management strategies must reflect these differences.

Malcolm T. Sanford
Bldg 970, Box 110620
University of Florida
Gainesville, FL 32611-0620
Phone (904) 392-1801, Ext. 143 FAX: 904-392-0190
INTERNET Address: MTS@GNV.IFAS.UFL.EDU