APIS Volume 14, Number 8 August 1996
In this issue
- The World's Beeswax--Fouling the Collective Nest
- More Thoughts on AFBControl
- September Panhandle Seminar
- Winter Losses--Back to Basics
THE WORLD'S BEESWAX--FOULING THE COLLECTIVE NEST
Most beekeeping products are consumable items. They can be looked at as transitory (i.e. short-term assets on the beekeeping balance sheet). One, however, has traditionally been in the long- term asset category. This is beeswax, that marvelous substance only the honey bee can produce. Although it can be converted into other products (waxes, cosmetics), a huge amount is recycled by the beekeeping industry and given back to the industrious insects that made it as foundation for their nest.
Along with those of honey (see May and June 1996 APIS), beeswax prices have escalated, though not necessarily for the same reasons. In the February issue of BEE BIZ (No. 2, 1996, pp. 3), Editor Matthew Allen analyzed this phenomenon. For many years, the market was split. Top-quality wax from Africa, the Americas and Australia was viewed differently than that of the Far East, mostly from China. The latter was often adulterated by paraffin and, thus, restricted to polish and candle use. The price differential between these two wax sources is now closing, Mr. Allen concludes, as demand for use in luxury items, confectionery and fancy food products increases, and so the price may remain high for some time. That's the good news. The bad news is that the world's beeswax is becoming more fouled each day, a tradeoff in controlling the Varroa mite.
Ever since beekeepers began using pesticides inside living bee colonies (see December 1987 APIS), there have been concerns voiced about colony contamination. Most had to do with honey; these are reduced considerably now with appropriate use of Apistan(R). Few, however, considered the possible effect of long- term widespread use of the contact pesticide fluvalinate on the beeswax supply.
No longer is this the case. Writing in the same issue of BEE BIZ as Mr. Allen (p. 4) about the 1995 Apimondia meeting in Lausanne, Switzerland, Clive de Bruyn reported that high residue levels of fluvalinate have been found in beeswax. Because of the nature of the molecule, he concluded, it bonds with the wax, making it almost unremovable. The Australian Bee Journal (quoted from June 1996 Bee Culture, p. 376) says virtually every kilogram of European wax is contaminated, most likely because of recycling fluvalinate-impregnated wax for foundation.
European beekeepers, therefore, are examining their beeswax more closely than in the past, and not using heavily contaminated product for foundation. Dr. Peter Rosenkranz, University of Hohenheim reported at the Fifth Ibero Latin American Beekeeping Congress in Mercedes, Uruguay (June 1, 1996) that residues from two to 20 milligrams of fluvalinate per kilogram of beeswax have been found. He says these levels might be enough to cause pesticide resistance to develop in Varroa. Mr. de Bruyn says that so much resistance can already be seen in certain districts of Italy, France and Germany that beekeepers are being advised to abandon all pyrethroids (chemical relatives of fluvalinate) in favor of other chemicals.
If levels of fluvalinate get too high, might there not be concern that the honey bees themselves will be poisoned by the chemical designed to rid them of Varroa (see April 1992 APIS)? There is some hope that beeswax from places that don't have Varroa would dilute the worldwide supply, according to the Australian Bee Journal, as referenced in Bee Culture. However, it concludes that a return to fluvalinate- free wax, would take an estimated fifty years, provided there was no chemical usage for that time period.
MORE THOUGHTS ON AFB CONTROL
I received some feedback on the article in the May 1996 APIS on American foulbrood (AFB) control in New Zealand and Florida. In that issue, I quoted Mr. Nick Wallingford, who said there was evidence that AFB will not develop unless more than 500,000 spores are fed to a honey bee colony. Dr. H. Shimanuki of the Beltsville Bee Research Laboratory states that according to Sturtevant (J. Agric. Res.:45(5), pp. 257-85), the minimum infective dose is 50,000,000 spores. There is also research in this area establishing an acceptable level of Bacillus larvae spores in honey. According to Dr. Shimanuki for individual one-day-old larval feeding, the LD50 for Bacillus larvae is 35 spores.
LD50 is a statistical term; it is the level that 50 percent of tested individuals will show symptoms and die. This is not an absolute measurement because the susceptibility depends on the genetic makeup of the individual larva. Beyond this, it is difficult to infect any colony using Bacillus larvae-spore contaminated honey or nectar. One reason is that neither is fed directly to susceptible-aged larvae (approximately 54 hours after egg-hatch). Larvae are only fed jelly made from worker-bee pharyngeal glands. Finally, foraging bees that have mouthparts more likely to be contaminated with the spores usually do not feed larvae.
The ability of adult bees to detect and remove larvae varies among bee stocks, according to Dr. Shimanuki. He is unable to confirm Mr. Wallingford's source's statement that diseased larvae are detected by workers before they show visual symptoms of the disease (see May 1996 APIS).
The key to American foulbrood control is inspection, Dr. Shimanuki says. It is difficult, however, to determine whether these efforts are adequate and/or cost-effective in most situations (see August 1991 APIS). Several levels of detection can exist, including anything from looking for spores in honey to what most inspection services do--identifying visible symptoms in the field. This also is complicated by what level of control is considered acceptable. Eradication is nearly impossible, even in a country as small as New Zealand, Dr. Shimanuki concludes. In most areas, AFB can be controlled, but beekeepers must inspect colonies more frequently, identify the disease when it is present and take corrective action immediately.
While at the Fifth Ibero Latin American Congress on Apiculture held May 30 through June 2, 1996 in Mercedes, Uruguay, I learned what can happen when AFB gets out of hand. Since it was first discovered in Argentina in 1989 (see November 1989 APIS), the beekeepers in that country have gone through three stages in controlling AFB, according to Marcelo del Hoyo of the veterinary faculty, University of Buenos Aires. The first was denial, when the name American foulbrood was not uttered. When the disease was finally recognized in affected areas, beekeepers tried to combat the problem locally, but it was still ignored elsewhere in the country. The present stage is a mature condition where most good apiculturists have been exposed to the disease and have at least temporarily treated the problem.
The fact that Argentinean beekeepers went through the above phases, however, appears to have led to something more serious than in other parts of the world. It is the only country to my knowledge where Bacillus larvae (known there as Paenibacillus larvae) has become resistant to oxytetracycline (see June 1990APIS). This was confirmed in a study reported at the Mercedes congress by A. Alippi and M. Aguilar (National University of Mar de la Plata). They used biochemical techniques (PCR) to analyze bacterial DNA. Resistance was found in only 28 percent of samples, but this translated to 58 percent of tested locations in the country. These results support the theory, according to the authors, that beekeepers used antibiotics to excess as an alternative to burning colonies. This behavior, along with inadequate doses of a wide range of products of dubious origin and quality employed as a preventative, appear to have favored the appearance of resistant bacteria.
Argentine researchers reported on another product, tylosin lactate (evidence of its effectiveness was first published by John Hitchcock and colleagues at the Laramie Bee Laboratory in the Journal of Economic Entomology. 63:1, pp. 204-207, February, 1970), which they say will control the disease as an alternative to Erythromycin and oxytetracycline. M. del Hoyo also listed a suite of controls now used by beekeepers, including burning colonies, using packages to move bees off contaminated hives, making splits into clean equipment, applying chemotherapy and various sanitation procedures (dipping in hot wax and lye solution and scorching supers). These must be used in conjunction with inspection at least every 90 days, he concluded, as one abandoned diseased colony can undermine a control program that has taken years to implement.
Given the importance of inspection services, Dr. Shimanuki says some time should be given to analyzing their role in the current beekeeping scene. Is it simply to find and destroy colonies with AFB or to provide other services to the beekeeping community? If the former is the case, he suggests leaving commercial beekeepers alone (except for spot inspections) and concentrating on part- timers and sideliners. He minimizes the influence of feral colonies in disease transmission; their present demise because of Varroa would support that position even more.
The Florida bee inspection program seems to have indeed evolved away from its original mandate of identifying and burning AFB infected colonies toward broader educational and service functions (see November 1992 APIS). This seems reasonable considering the introduction of tracheal and Varroa mites and the continued concern about African honey bees. Coping with all of the above issues takes time and energy; the Florida inspection service does not have the resources to do the same for these as it does for AFB.
Meanwhile experience shows that AFB remains a threat to all beekeeping operations and that complacency or distraction can quickly lead to problems (see May 1990 and May 1996 APIS). The identification and control of American foulbrood, either through a formal inspection service and/or by the beekeeper, therefore, must continue to be an important part of any managed apiary.
PANHANDLE SEMINAR
The next panhandle beekeeping seminar will take place September 7, 1996 at the Langley Bell 4-H Center, Nine Mile Rd., Pensacola, FL. This is the fourth in a series of seminars sponsored by the Escarosa Beekeeping Association (see September 1995 APIS). The event begins at 8 a.m. and lasts all day. It features open-hive demonstrations in the morning, a catered lunch and presentations on garden pollination and AFB and Varroa control issues in the afternoon. The cost is $20 ($10 for students). Bring your own veil, gadgets and items to auction. Send check, payable to Escarosa Beekeeping Association, to Sylvia Bullard, 9801 Lyman Drive, Pensacola, FL 32534, ph 904/478-7690. For more information on the program call Owen Powell 904/968-0535.
WINTER LOSSES--BACK TO THE BASICS
There has been a lot of discussion about winter loss last year. Dr. Eric Mussen (quoted in June 1996 issue of The Speedy Bee from his newsletter, From the UC Apiaries, May/June 1996) revealed some "negative results" he found studying amitraz to control tracheal mites. He states: "An overview of all these studies (those conducted by Dr. Mussen and colleagues) suggests very strongly that contact applications of amitraz in hives of bees do not provide adequate control of tracheal mites ...in cool or cold temperate climates." Thus, in spite of other investigations that "paint" amitraz more favorably, he suggests that popular misconceptions about the value of amitraz as a tracheal mite control could in fact be contributing to heavy winter loss. Adding fuel to this fire is the fact that presently NO FORMULATION OF AMITRAZ IS LEGAL TO USE ON HONEY BEES.
How much tracheal mites contribute to winter loss remains an enigma. A. Phibbs ("Three Year Survey of Varroa and Tracheal Mite Infestations of Honey Bees in Wisconsin," American Bee Journal, Vol. 136:8, pp. 789-592) was unable to correlate tracheal mite frequency and mortality. She concludes, however, that mite parasitism appears to make colonies more vulnerable to other diseases. A spring 1994 survey conducted during the study showed 66 percent of colonies with "signficant" infestations of Nosema apis.
Dr. Tom Webster reported (quoted in the June 1996 issue of The Speedy Bee from Kentucky Bee Line May/June 1996) an average 1995 winter loss of 45 percent by 38 beekeepers. Only three individuals had not used Apistan (R), resulting in 100 percent loss. For tracheal mite control, half used shortening/sugar mixture and got better winter survival than those that did not (see October 1994 APIS). However, those using menthol had the same loss as those not using the product (see November 1988 APIS). But beekeepers using Apistan (R), vegetable shortening and Fumidil-B (R) (for nosema control) lost 19 percent of colonies, while those not using Fumidil-B (R) had 38 percent loss. According to Dr. Webster's calculations, for a $12 to $15 dollar investment in Fumidil-B (R), about six to eight times as much can be saved. Note: Fumagillin is the active incregedient in Fumidil-B (R) and can at times be found in other products like Nosem-X (R) or Fumagillin-B (R).
This goes back to some beekeeping basics, as stated by Mr. Glen Stanley, retired Iowa bee inspector, while giving advice on controlling tracheal mites "...why not begin fighting the battle where it would do the most good by getting bees cleared of nosema first." (see July 1994 APIS). The same issue was also raised more recently by Andrew Matheson discussing why beekeepers have so quickly adopted vegetable oil patties for tracheal mite control, yet do not routinely use fumagillin for nosema. (see December 1995 APIS).
Sincerely,
Malcolm T. Sanford
Bldg 970, Box 110620
University of Florida
Gainesville, FL 32611-0620
Phone (904) 392-1801, Ext. 143 FAX: 904-392-0190
http://www.ifas.ufl.edu/~entweb/apis/apis.htm
INTERNET Address: MTS@GNV.IFAS.UFL.EDU
©1996 M.T. Sanford "All Rights Reserved
