APIS Volume 11, Number 3, March 1993
In this issue
- Varroa Mites--Spreading Among Colonies
- Where are the Bees?
- Caribbean Apicultural Development
- Mite Discussions
- National Honey Board's Taking Pride Program
VARROA MITES-A COMMUNITY PROBLEM?
Many beekeepers are individualists. Experience trying to get beekeepers to act in unison reveals at best a laissez faire attitude about cooperating together on certain projects. In fact, the history of associations and other groups dedicated to beekeeping issues more often than not shows that beekeepers actively work against each other. Evidence from seminars and other educational events also supports the thesis that beekeepers are content to go about their business independent of their neighbors.
To non beekeepers, the individuality of many beekeepers seems strange, for honey bees are just the opposite. They are the most social of creatures. A single individual in a beehive, be it queen, drone or worker, means nothing. Survival depends on working together for the common good. If this is a good strategy for bees, then why do beekeepers not subscribe to it?
In the past, the rugged individualistic beekeeper could function well enough. In fact, the craft demanded one be a self- starter and an innovator. Times were simpler (or seemed so) and there were fewer non beekeepers with which to interact. Advances in transportation and increases in growth and development have affected rural and urban areas. This has resulted in problems often associated with activities of other people. For the beekeeper, this has meant everything from death of colonies because of pesticide application to permanent loss of beehive locations.
In 1987, Varroa mites were detected in the United States, forever changing the face of beekeeping. Fortunately for U.S. beekeepers, a technology was in place to deal with the Varroa mite, a parasite that effectively kills most honey bee colonies it invades. Certain chemical control methods were legal and labelled; they reduce mite populations in beehives by over 95%. It is important to understand, however, that although chemicals control the mite population, the threat is not eliminated and populations can resurge dramatically. In all probability, the beekeeping community will have to deal with Varroa mites from now on.
Although chemical control has blunted the effects of the mites in individual bee colonies, it also allowed a myth to perpetuate itself. This is the belief that Varroa could be handled just like other problems in beekeeping by the individual beekeeper whenever and wherever it was deemed convenient and appropriate. The dynamics of Varroa-bee interactions, however, suggest something different.
It is now recognized that Varroa mites are not only a honey bee community problem, they are a beekeeper community problem. This idea was brought into focus by Marion Ellis, Nebraska State Apiarist at the American Beekeeping Federation meeting in Kansas City. In his presentation, he referred to an article in the December, 1991 issue of American Bee Journal entitled "How Varroa Mites Spread," by Dr. Eva Rademacher (pp. 763-765).
Through a series of experiments, Dr. Rademacher found that Varroa mites rapidly spread among colonies in a beeyard. The main cause of growth of mite infestation is drifting parasitized bees, not natural increase of mites within individual colonies. The conclusion: It is not the infestation of a single colony, but rather the general rate of infestation for the entire yard that should be monitored.
Comparing two locations where infested apiaries were within two kilometers (1.2 miles), Dr. Rademacher also showed re-infestation rates to be dramatically different based on infestation rates of nearby apiaries. If the rate was 900 mites/colony or less (low invasion pressure), re-infestation in apiaries in close proximity was three times more than normally expected; if 900 mites/colony or more (high invasion pressure) were present, the figure rose to 11 times normal. Thus, according to Dr. Rademacher, "...it is not 'hive mites' which endanger the colony, but rather the 'immigrants.'" Given this evidence, she suggests:
- Nuclei or natural swarms which have been treated for Varroa, should be placed at locations where a low mite fluctuation from the surroundings (low invasion pressure) can be expected.
- It is not helpful to treat just one or several of the colonies in a beeyard because of the danger presented by other infested colonies.
- Beekeepers with beeyards rather close to each other should make arrangements to medicate their entire stock at the same time, because of the invasion pressure which leads to a rapid increase of mite population within only several weeks.
- Invasion pressure also plays an important role when colonies are moved to other areas. Not only will a beekeeper want to determine the level of infestation in the new foraging area, but the keeper in that area should also be concerned about the level of infestation of incoming colonies.
- Natural swarms should be medicated before being incorporated in the beeyard.
- It is also important to prevent robbing. It has always been accepted that the robbed colony suffers. Now the robbing colony itself can be the victim from by invading mites.
The message is clear. Effective Varroa control should be undertaken as a beekeeper community effort. If not, then presence of nearby infested colonies will quickly undermine the money and effort any beekeeper expends to control mite populations.
WHERE ARE THE BEES?
A colleague who works in the Master Gardener Program asked me the other day about the feasibility of establishing beehives in urban areas. Many home gardeners, it seems, are observing declines in honey bee populations leading to reduced yields. They are asking where the bees are.
I'm not sure why there might be fewer honey bees than before, but in Florida, the Varroa mite is a good possibility. It has now been about five years since introduction of this parasite, more than enough time to seriously weaken, if not kill outright, a majority of unmanaged colonies. Feral or wild bees no doubt contributed greatly to home gardens as pollinators in the past. However, these insects can no longer be taken for granted. It appears that a more "pro-active" pollination program is in order, the purposeful placement of honey bee colonies in areas where pollination appears to be limited.
In educational parlance, another "teachable moment" is at hand. This concept arises from the idea that you can only educate when you have a person's attention. Now is the time, therefore, to ensure that every home gardener knows how valuable and from where his/her pollination comes from. There are potential liability problems in locating honey bee colonies in urban areas, but the risks are minimal if certain precautions are taken. An added advantage over pollination potential is the fact that actively managed colonies will provide competition for wild African bees when they arrive. Those associated with beekeeping should take advantage of this opportunity, one borne out of the adversity of Varroa mite predation. There has never a better time to put honey bees and beekeepers in their rightful place as valuable contributors to the food supply.
CADA NEWSLETTER PUBLISHED
I am in receipt of the second issue of the newsletter published by the Caribbean Apicultural Development Association (CADA). At the recent meeting of the 5th International Conference on Beekeeping in Tropical Countries, the first Board of Directors was elected. The President is Mr. Mohammed Hallim (Trinidad and Tobago) and the Secretary is Dr. Daniel Pesante (Puerto Rico). This issue of CADA newsletter contains an account of how the Association helped re-establish honey trading between St. Lucia and Martinique, and articles about Dr. Eva Crane, understanding swarming in the subtropics, and why the Africanized honey bee is an unwanted guest in the Caribbean.
Now that CADA is getting off the ground, the Association is in need of more members. Anyone in the region, from Florida, the Caribbean or the Latin American mainland (two mainlanders [Venezuela; Surinam] are officers) should contact Dr. Pesante, Animal Science Dept., P.O. Box 5000, College Station, Mayaguez, PR 00681, ph 809/265-3854, fax 809/265-0860. The Association is also soliciting memberships from those interested in participating in CADA activities. Dues of $15.00 per year should be sent to the Treasurer: Jorge Murillo Yepes, P.O. Box 612, St. Georges, Grenada.
MITE MEETING
I am in receipt of a report generated by the Bee Mite Informal Meeting held at the Entomological Society of America convention in Baltimore, December 7, 1992. It contains some interesting tidbits that all may not be aware of.
Surveys in Bee Culture indicated that tracheal mites were reported in 30% of states in 1984, and this rose to 80% by 1987 and 100% by 1992. Large losses were reported in northern areas where bees were confined for long periods. Treatments reported by bee inspectors in 1992 were: 51% of beekeepers not treating; 37% treating with menthol crystals; 21% using grease patties and the rest using illegal treatments. Tracheal mites did not appear to affect honey production, but did result in decline in number of beekeepers. Although tracheal mites have been known for 100 years, there is no information on what they are actually doing to colonies. Major suspicions are they pass on viruses and bacteria which do the actual damage to colonies.
Varroa has been found to be involved with organisms called spiroplasms. These can be found in nectar and have been implicated in large-scale dieoffs. In bees infected with spiroplasms, all Varroa associated with them also have spiroplasms.
A good many experiments are being carried on with oils and other substances to control populations of both mites. These include hot corn oil, garlic oil, thymol, cinnamon oil, Listerine (R), which contains menthol, and even salad dressing (oil plus vinegar). Questions that need to be addressed continue to be: finding resistance mechanisms, determining sampling technology, developing life tables for mites, and figuring out what bees are doing with oil and grease placed in colonies.
NHB TAKING PRIDE PROGRAM
The National Honey Board's PRIDE program is off and running. You can now get a two-color decal for your truck, van, shop or production facility. It's free when you send for the PRIDE education kit. The purpose of this program is to support safe beekeeping and honey handling. This will add to honey's already sound reputation as a pure and natural product. For more information, contact the Board, 421 21st Ave., Longmont, CO 80501- 1421, ph 303/776-2337.
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
