Argentine Beekeeping Strategies for Disease Control without Residues in Honey (2010)
Prof. Norberto García Girou M. Sc.
NEXCO S.A. and Universitad Nacional del sur Argentina
Ever since nitrofurans were discovered in 2003, Argentine beekeeping has experienced a critical challenge: solving the problem of residues in honey. A lot has been learned from the best practices in beekeeping in the past seven years, and traceability has been imposed. Meanwhile, beekeepers have to deal with three main diseases that affect bees: Varroa mites, American Foulbrood (AFB), and Nosema. Through this presentation, I put forth a strategy for dealing with each of these diseases and addressing the problem of residues in honey.
First, the control strategy for Varroa should be based on the adequate rotation of drugs (spring and fall), avoiding consecutive treatments with the same drug. An appropriate diagnosis of Varroa mites before and after the treatments is a valuable tool to make subsequent decisions about how to control this disease. With an accurate initial diagnosis, unnecessary treatments can be avoided (thus mitigating the residue problem) and the development of drug-resistance by the mites can be delayed.
Second, the use of antibiotics for control and prevention of American Foulbrood should always be avoided. Antibiotics do not kill AFB spores and contaminate honey. Additionally, its residues are not tolerated in many honey-importing countries. Thus, AFB must only be controlled through management practices.
Finally, the main strategy for the control of Nosema disease should be its prevention through the appropriate handling of factors that predispose the appearance of this disease. For other diseases, such as European Foulbrood, chalkbrood disease and wax moths, only appropriate management practices are suggested.
Quality requisites for food products have steeply grown during the last few years. This is particularly true for honey. Consumers are prone to pay much more for honey than any other sweetener because they consider it a natural product free of contaminants. During the last years, however, we have learned that many contaminants of different nature and origin may be present in honey.
We have all witnessed a constantly growing sensibility of detection techniques and the frequent introduction of new quality parameters in routine protocols of honey analysis. This has gradually transformed the production and commercialization of honey into a more complex and professionalized activity.
In this context, there is a growing need for effective channels of communication between beekeepers and honey dealers.
Argentine beekeeping, traditionally focused on the international honey market, has faced many challenges during the last two decades in order to satisfy the quality requirements of the strictest honey importing countries.
Recently, the Argentine Institute of Agronomic Technology (INTA) and Nexco S.A. signed a strategic agreement for the production and commercialization of large volumes of high-quality honey.
The Argentine National Institute of Agronomic Technology (INTA), through its National Beekeeping Program, has also been developing and transferring beekeeping technologies for the production of high quality honey during the last few years. Sound generation of beekeeping technologies and their transference using associative models have been at the core of INTA’s main efforts.
NEXCO, the main Argentine honey exporting company, has also been working to improve the quality of Argentine honey through the application of high quality standards for the analysis (ISO 17025) and processing of honey (ISO 22000). They also aim to offer technical assistance to beekeepers in order to improve different aspects of their operations.
In order to comply with the increasing standards of the world honey market, INTA and NEXCO are now working together in a five-year program to:
- develop a quality system “from the hive to the drum”, including Good Beekeeping and Manufacturing Practices programs with technical assistance to beekeepers;
- study the dynamics of contaminant molecules in the hive (antibiotics, pesticides, and more recently pirrolizindine alkaloids);
- characterize different types of Argentine honeys according to their floral and geographical origin, also considering potential sources of pirrolizidine alkaloids in honey.
This article briefly describes beekeeping practices suggested to beekeepers who sell their honey to the company in order to avoid residue problems.
Location of the Apiaries
In order to prevent the outbreak of bee diseases - and subsequently avoid the eventual use of chemical treatments - and to minimize the risk of contaminants of external origin, the following are a few recommendations for choosing an adequate site for the location of an apiary:
- The hives should be located at a distance that should not be less than two kilometers away from populated areas where there is a proven increase in the probability of contagion of American foulbrood through used beekeeping materials being stored in sheds and warehouses.
- The same distance must be taken into account in the case of opencast rubbish dumps and industrial settlements.
- The location of apiaries near neglected apiaries and beeswax rendering factories should be avoided.
- In big cities with a significant degree of environmental pollution, the minimum distance required for the location of the apiaries is five kilometers.
- For cereal storage plants, the applicable distance is of at least a thousand meters due to possible contamination of the surroundings with chemicals used for curing grains.
- Always abide by local, provincial and national legislations.
These are some of the beekeeping practices recommended for application throughout the year in order to improve bee health, reduce the use of drugs and avoid honey contamination with bee feeds.
- With the last harvest round or the formation of late summer nuclei, the space of the hive should be reduced to a single brood chamber. For that reason at the time of the autumn Varroa control and artificial feeding all the honey supers should be in store to avoid their eventual contamination.
- Simultaneous curing processes and artificial feeding should be avoided. These tasks should be carried separately during different work cycles.
- Artificial feeding of colonies for wintering should be over by the autumn, and should preferably be complete by April or May.
- Supers should be stored in a roofed and ventilated warehouse, ensuring the correct control of rodents (traps, cats, or, in case of need, products containing warfarin). At the time of stacking the supers, the honeycombs should be classified, carefully discarding the black ones.
- During the first check ups in spring it is recommendable to take advantage of the existence of black empty combs in the brood chambers for their replacement.
- Artificial feeding should be suspended after supering, avoid the use of syrup when a nectar flow is suspected. Neither should syrup be fed if there is an interruption during a nectar flow.
- Only cane sugar (sucrose) or high fructose corn syrup for human use should be used for the artificial feeding of bees.
- In the preparation of syrup, adding any other substance but sucrose and drinkable water is NOT allowed. To ensure the quality of the water used, the field preparation of syrup with water of unknown quality is forbidden.
- For sanitary reasons, it is not allowed to use honey or any of the products that contain it to feed bees.
- For sanitary reasons, the use pollen for the preparation of protein complements is not allowed, and neither is the use vitamin and/or protein concentrates developed for other types of animal exploitation.
- The combs from the brood chamber should not be moved up onto the supers.
- The foundation wax should be free from residues that can result as risky (acaricides).
- In case of use of foundation wax of an unknown source, its purity should be checked with an appropriate analysis.
- The combustion material of the smoker should be of vegetable origin, such as dry grass, pine needles and dry leaves of Eucalyptus. The use of timber shavings treated with preserves is not allowed. Only shavings from natural timber are allowed. To make it easier to light the smoker, ethyl alcohol can be used, avoiding the use of hydrocarbons.
- During the harvest, the smoker should never be placed over the frames with honey in order to avoid possible contact of the honey with the dripping of combustion products that in some cases are produced by the smoker. The smoker should be frequently cleaned to minimize dripping.
- Honeycombs containing brood should not be harvested. Only properly ripened honey should be collected. As a general guide, the honey is considered ripe when 60 % or more of the comb is sealed. It is recommendable to harvest in the morning to minimize the collection of honeycombs with significant quantities of nectar newly gathered that spills after being shaken by the beekeeper.
- Honeycombs from the brood chamber should not be harvested nor put up on the supers due to their higher contamination with acaricides.
- The use of chemical bee repellents is NOT allowed.
- Under no circumstance should the supers containing honey be placed directly on the ground.
- All the new material that is added to the exploitation should be preserved by immersion in hot microcrystalline wax or paraffin wax with a melting point no less than 60 degrees centigrade. Bottom boards, supers, and covers are included. The use of lead containing paints and/or burnt oil, kerosene or toxic preservatives are not allowed. All the material should be made of timber and of standard sizes.
- The supers full of honey should be placed on trays on the vehicle to be transported to the extraction plant. It is recommended to place a lid, together with a canvas cover, over each pile of full honey supers to prevent dust and rainwater from going into the combs during the transportation to the extraction plant.
The transportation of full honey supers together with any other kind of load should be avoided.
- The vehicles and trailers used for the transportation of honey supers should be adequate so as to ensure a perfect seal, avoiding therefore the contact of honey with dust or rainwater.
- After each journey the vehicles should be washed carefully, together with the canvas covers, trays and beekeeping clothing.
The Honey Extracting Plant
In all cases, honey extraction must be carried out in authorized plants and in compliance with the resolution by SENASA number 353/02. SENASA is the Argentine Animal Health Authority. Good manufacturing practices, appropriate honey extracting facilities, and traceability are the principal aims of the resolution.
All the staff should be constantly informed and trained on the diagnosis, prevention, and treatment of bee diseases. All hive treatments should be recorded and the personnel should have a thorough understanding of the potential hazards of pesticides to human health.
The main strategy for the control of Nosema disease should be its prevention through the appropriate handling of factors that predispose the appearance of this disease.
- Early formation of late summer splits composed of at least five frames of sealed brood and an abundant population of adult bees is recommended so as to ensure strong colonies capable of collecting sufficient pollen during the autumn. Winter bees with a high-body protein are the basis for effective Nosema control.
- Abundant artificial feeding in autumn that is enough to cover the requirements both in the fall and winter without the need from undergoing stress of winter feeding. Artificial feeding should be completed during the first part of autumn.
- The apiaries should be located in sunny spots in order to facilitate frequent cleansing flights to the bees and avoid the evacuation of the bees’ feces inside the hive with the consequent dissemination of Nosema spores.
- Replacement of old combs from the brood chambers and honey supers is recommended since these old combs may hold a reservoir of Nosema spores.
- If an attack of Nosema has taken place, the only authorized drug for its control is Fumagilin with a withholding period of at least 90 days. The management unit should be the apiary, so the cure should be only done in the affected apiary.
The use of antibiotics for control and prevention of American Foulbrood should always be avoided. Antibiotics do not kill AFB spores and contaminate the honey. Its residues are not tolerated in many honey-importing countries.
Recuperation of hive material
If the number of infected hives is low and the time and effort needed to recuperate the bee colony is not profitable, the colony should be killed and the wooden material recovered. In this case, the procedure should be as follows:
- The bees should be killed with a pyrethroid based insecticide when they are not flying.
- The hive must be removed from the apiary.
- The frames with brood and bees should be burned in a pit large enough to contain the honey and wax and the remains buried, in order not to leave honey exposed to robbing.
- The rest of the wooden parts of the hive should be sterilized by immersion in hot paraffin wax at 150-160 degrees centigrade for 10 minutes.
- Scorching the inside of hive parts is another possible sterilization method.
Recovery of the bee colony
The recovery of the colony of bees is only advisable at the early stages of the disease and when the population of adult bees is big enough to justify the required work. This recovery is possible if it is carried out in springtime or summertime when the bees are still able to build new comb.
One method of saving bees from an infected colony consists of making a package of bees, leaving it for 48 hours in the dark so that the bees consume the contaminated honey from their honey stomachs and then transfer it to a decontaminated hive with frames containing foundation wax and a feeder.
Another procedure, perhaps less effective but still viable, consists of transferring the bees form the infected colony directly into a new hive with frames containing new foundation wax and feeder.
If the number of affected hives is worthwhile, a quarantine apiary near the residence of the beekeeper can be established. In this quarantine apiary all hives with symptoms of American Foulbrood can be grouped in order to keep track of the handling to eradicate the disease.
Although no strain of bees is immune to American Foulbrood, there are lines of bees with different degrees of resistance. The importance of hygienic behavior in the resistance of the bees to this brood disease has been proved. That is why the introduction of highly hygienic queens is strongly recommended.
Some useful hints for the prevention and control of the disease are:
- Develop the ability to detect the disease early on.
- Monitor the brood chambers periodically. Specially inspect weak or non-performing hives.
- Autumn time monitoring is essential to avoid death and eventual robbing of infected hives during the winter.
- A pre-harvest check decreases the possibility of dissemination of the disease due to the exchange of wet supers with remains of honey.
- Avoid transferring frames of brood or honey between hives without checking brood for American Foulbrood symptoms.
- In case of a serious disease problem, return wet supers to the same apiary.
- Remove all dead hives from the apiaries and store them in bee proof conditions.
- Avoid feeding hives with honey and/or pollen, resorting to the use of substitutes if necessary.
- Sterilize the contaminated beekeeping material adequately.
- Incorporate queen bees with high hygienic behavior.
- If the percentage of affected hives is low, normally it is recommendable to directly eliminate them.
- The recovery of affected bee colonies should follow the procedure of shaking or packaging (described above).
The effectiveness of the different acaricides used for the control of the Varroa mites vary mainly due to the development of drug resistance by the mite. For that reason, it is essential that the beekeeper be constantly informed in order to achieve an effective control for this disease.
The control strategy should be based on the adequate rotation of drugs avoiding consecutive treatments (spring and fall) using the same drug. If an additional treatment is needed in the springtime, only organic acaricides should be used.
An appropriate diagnosis of Varroa mites before and after the treatments is an irreplaceable tool to make decisions about how to control this disease. With an accurate diagnosis, unnecessary cures can be avoided and the appearance of drug-resistant mites can be delayed.
The most practical method for quantitative diagnosis of mite infestation rates is bee sampling to estimate the level of infestation on the adult bees. In this method, between 300 and 400 worker bees are collected from the brood area of a colony (preferably from different brood frames) into a jar. They are then covered with 95% ethylic alcohol. The sample must be shaken vigorously to achieve the detachment of the parasites. The separation of mites and bees is achieved by using a tray and screen. The sample is poured into the screen so that the bees remain in the basket, while the mites fall to the bottom of the tray.
It is important that the level of alcohol in the tray and the sieve is high enough so as to allow the bees to float and disperse. The bees must be shaken in the basket to free any mites that may be entangled with the bees. Finally, a quantitative estimate of the infestation rate can be obtained by counting the mites and the bees and expressing the result in terms of the number of mites per 100 adult bees.
To estimate the sanitary state of an apiary in relation to Varroa disease, a random sample of 5- 10% of the hives should be performed, considering that the infestation levels may greatly vary within the apiary and between apiaries.
The following control strategy is described in terms of active ingredients in order to avoid a direct mention of commercial products. Each beekeeper may choose between the available authorized products in order to find one that contains the chosen active ingredient.
Apiaries in which the resistance to the drug Amitraz has not been observed or apiaries in which this drug has not been used repeatedly for the last treatments
Once the honey harvest is over, apply Amitraz based strips. After a fortnight, a quantitative estimate of mite infestation rate should be made by sampling adult bees.
a) If the prevailing infestation rate is under 0.5%, no additional autumn treatment is necessary. In that case, by the end of winter a second treatment with Flumethrin based strips is recommended. Strips should not be left in the hive for more than 42 days. Again, after 15-21 days of this second treatment the mite infestation rate should be measured:
a.1) If the prevailing infestation rate is less than 0.5%, no more treatments should be carried out until the end of the harvest.
a.2) If the prevailing infestation rate is more than 0.5%, a springtime control based on oxalic acid should be carried out.
- b) If the prevailing infestation rate after the autumn treatment based on Amitraz turns out to be over 0.5%, a second control will be carried out in autumn with Coumaphos based strips. In this case, during springtime a control based on oxalic acid is recommended, respecting a withholding period of 60 days.
Apiaries in which the resistance of the drug Amitraz has been observed or apiaries in which this drug has been used repeatedly for the last treatments
Once the harvest is over, apply Coumaphos based strips. After fifteen days, the mite infestation rate should be estimated.
a) If the prevailing infestation rate is less than 0.5%, no additional autumn treatment should be done. In this case, the beekeeper should wait until the end of winter to carry out a second treatment with Flumethrin based strips. After 15-21 days of this second treatment, the prevailing mite infestation rate should be measured:
a1) If the prevailing infestation rate is less than 0.5%, no more treatments should be done until the end of the harvest.
a2) If the prevailing infestation rate is more than 0.5%, a springtime treatment based on oxalic acid should be carried out.
b) If the prevailing number after the autumn treatment based on Coumaphos turns out to be over 0,5% a second control will be carried out in autumn based on Flumethrin based strips. In this case, a springtime treatment based on oxalic acid is recommended, always respecting a withholding period of 60 days.
For other diseases, such as European Foulbrood and Chalkbrood disease applying any kind of treatment with drugs to the bee colony or for the disinfection of the beekeeping material is NOT allowed. They should only be treated with appropriate management practices.
Young vigorous queens and large populations of worker bees are the basis for minimizing losses due to European Foulbrood.
Avoiding sudden temperature changes inside the hive, ensuring well populated colonies, and introducing highly hygienic queens are the best strategies to avoid an outbreak of Chalkbrood disease.
Prof. Norberto García Girou (M. Sc.)
NEXCO S.A. & Universidad Nacional del sur Argentina