ANTIVARROA TREATMENTS, HEALTH OF BEES AND QUALITY

OF HONEYdr Zbigniew Lipiński

POLAND

ANTIVARROA TREATMENTS

ANTI VARROA TREATMENTS

HARMFULL EFFECT OF VARROA DESTRUCTOR ON HONEY BEES

HARMFULL EFFECT OF VARROA DESTRUCTOR ON BEES

HARMFULL EFFECT OF VARROA DESTRUCTOR ON HONEY BEES

Varroa mites not only cause significant damage to the bees by feeding on their hemolymph, but also act as a vector for viral diseases like Acute Paralysis Virus (APV) and Chronic Paralysis Virus (CPV). The wounds inflicted by mites may also be contaminated with bacterial or fungal organisms. These secondary infections can be recognized based on typical symptoms associated with them and often lead to severe damage to the colony. In order to prevent this, it is crucial that colonies are monitored for Varroa infestation regularly and that measures to control the infestation are taken when necessary

De forming bee wing virus

TYPICAL MITE POPULATION DYNAMICS FOR A TEMPERATE CLIMATE

The main battle with varroa

Recognitionthrough fight

Unchecked, varroa can really multiply! A 12-fold increase is

typical in a short season consisting of 128 days of brood rearing (Martin 1998). However, its

population can increase 100- to 300-fold if broodrearing is

continuous! (Martin and Kemp 1997).

Varroa Population Dynamics

UP TO NOW MOST BEEKEEPERS HAVE APPLIED SYNTHETIC

PESTICIDES (ACARICIDES – VARROACIDES)

TO CONTROL THIS MITE IN THEIR COLONIES.

Product Trade Name Active Ingredient Chemical Class Apiguard thymol essential oil

Apilife VAR thymol, eucalyptol, menthol, camphor essential oil

Apistan fluvalinate synthetic pyrethroid

Apitol cymiazole iminophenyl thiazolidine derivative

Apivar amitraz fornamidine Bayvarol flumethrin synthetic pyrethroid Check-Mite+, Perizin coumaphos organophosphate

Folbex bromopropylate chlorinated hydrocarbon

generic formic acid organic acid generic lactic acid organic acid generic oxalic acid organic acid

LIST OF TREATMENTS SHOWN TO HAVE SIGNIFICANT EFFICACY FOR VARROA CONTROL

THE USE OF SYNTHETIC ACARICIDES HAS THREE MAJOR

DISADVANTAGES

1 – INFLUNCES BEE HEALTHKNOWN AS ADVERSE EFFECTS

2 – CONTAMINATES HONEYBEE PRODUCTS3 – CAUSES VARROA RESISTANCE

HEALTH OF BEES

HEALTH OF BEES & SYNTHETIC ACARICIDES

ADVERSE EFFECTS CAUSED BY THREE MOST COMONLY USED

SYNTHETIC ACARICIDES FOR CONTROL OF VARROA

FLUVALINATEFLUMETHRINE

AMITRAZ

Increased adult bee mortality for fluvalinate has been assessed at 2.7 bees/day over 60 days52. Significantly less (86% vrs. 97%) drones emerged from colonies treated with Apistan than control colonies, but survival was greater for both compared to varroa infested colonies (59%). Both varroa and Apistan caused reductions in drone body weight and various glands125

In queen cages, exposure to 1% fluvalinate for 3 days caused significant mortality in worker attendants and increased supersedure in queens. Exposure for 7 days caused significant mortality in queens31.

FLUVALINATE ADVERSE EFFECTS

Three experiments were conducted on queen and worker honey bees (Apis mellifera L) to assess effects of treatment with fluvalinate impregnated (Apistan®) strips. A 5-d treatment of worker bees (weighing 1.4 kg per group) in screen packages with a fluvalinate strip (2.5% a i, 2.5 x 13 cm) did not increase mortality. Overwintered laying queens (n = 30), and newly mated queens (n = 60) were treated in Benton mailing cages for 5 d with fluvalinate (Apistan Queen Tabs, 1% a i, 2.5 x 1.3 cm). All queen mortality occurred on d 4 and 5 of the treatment period, which is beyond the recommended 3-d-treatment. Neither group of treated queens exhibited a significant increase in mortality. However, attendant worker bees in the second trial exhibited a significant increase in mortality during treatment. No differences were observed in colony acceptance of queens, brood viability, or supersedure rates at 2 and 6 months post-exposure.

FLUMETHRINE ADVERSE EFFECTS

No increase in bee mortality was observed in a field study of honey bee tolerance to the chemical, and was the lowest of 6 chemicals tested52.

A preparation of amitraz (Apivarol) was found to increase mortality of 1-3 day old larvae (61% vrs. 83% for control)4. A fumigation strip of amitraz caused some bees to leave their hive and form clusters98. Fumigation strips also caused high adult bee mortality in package bees60.

AMITRAZ ADVERSE EFFECTS

N0 1MD

2 3 4 5 6 7 8 Σ 8MD

9 10 11 12 13 14 15 Σ

1 HC 40 42 13 9 8 1 3 116 HC 8 0 1 4 0 3 3 192 HC 110 3 3 1 2 0 3 122 HC 2 3 1 2 1 1 0 103 HC 9 34 11 5 4 3 0 66 HC 3 7 3 7 2 3 0 254 HC 15 31 6 4 1 2 1 60 HC 1 2 0 2 0 0 0 55 HC 47 7 3 2 1 1 0 61 HC 5 3 3 1 0 1 0 136 HC 51 29 10 5 8 1 7 111 HC 25 7 2 4 2 0 0 407 HC 33 17 6 8 1 3 1 69 HC 17 21 6 2 2 4 0 528 HC 30 19 9 3 3 2 2 68 HC 5 7 0 2 0 1 0 159 HC 24 28 13 11 1 0 0 77 HC 3 0 0 0 0 0 0 310 HC 20 21 12 8 3 0 0 64 HC 0 2 0 1 0 0 0 3Σ HC 379 231 86 56 32 13 17 814 HC 69 52 16 25 7 13 3 18511 HC 12 17 8 4 3 0 1 45 A 4 1 0 0 0 0 0 512 HC 9 26 22 4 5 4 3 73 A 0 1 0 0 0 0 0 113 HC 37 4 1 2 4 2 1 51 A 0 1 0 0 0 0 0 114 HC 13 37 15 5 1 0 1 72 A 1 0 1 1 1 0 0 415 HC 22 53 16 8 10 2 3 114 A 0 1 1 2 0 0 1 516 HC 34 37 7 5 4 2 14 103 A 3 0 2 2 1 0 0 817 HC 23 47 20 16 0 4 4 114 A 15 0 0 0 0 0 0 1518 HC 22 22 11 7 3 1 1 67 A 4 0 0 0 0 0 0 419 HC 24 44 32 22 14 12 1 149 A 9 0 0 0 2 0 0 1120 HC 8 9 1 2 1 1 1 23 A 29 2 1 1 0 2 0 35Σ HC 204 296 133 75 45 28 30 811 A 65 6 5 6 4 2 1 89

THERE ARE ALSO ADVERSE EFFECTS CAUSED BY THREE LESS

COMONLY USED SYNTHETIC ACARICIDES

FOR CONTROL OF VARROA

CYMIAZOLECOUMAPHOSBROMOPROPHYLATE

CYMIAZOLE ADVERSE EFFECTS

Adult bee deaths have been reported with Apitol61; 45. Cymiazole was found to be moderately toxic to honey bees when ingested at a rate of 3500ppm119. Cymiazole fed to bees reduced development of hypopharyngeal glands and increased the amount and acidity of rectal contents118.

COUMAPHOS ADVERSE EFFECTS

Increased adult bee mortality for Perizin has been assessed at 15.7 bees/day over 7 days52. Perizin was assessed as having a low toxicity for bees (LD50 = 14.39µg)78.

Use of Folbex did not cause adverse effects on queen lifespan, brood area or honey production7. Folbex did not affect brood survival compared to controls

BROMOPROPHYLATEADVERSE EFFECTS

ADVERCE EFFECT CAUSED BYESSENTIAL OILSTHYMOLEUCALIPTOLMENTHOLCAMPHOR

APILIFE VAR

THYMOL ADVERSE EFFECTS

Increased adult bee mortality for thymol has been assessed at 9.5 bees/day over 10 days52, although in another study only young larvae survival was affected (74-87% v. 89-95% for controls), with no differences in sealed brood or adult survival 102.

BY THE WAY

The kill rate of bees in a single bee hive can be classified as:

< 100 bees per day - normal die off rate 200-400 bees per day - low kill 500-900 bees per day - moderate kill > 1000 bees per day - high kill

APILIFE VAR ADVERSE EFFECTS

Colony development is not thought to be impaired by use of Apilife VAR91, although one study reported loss of 50% of bees in treated colonies over winter, and significant reductions in honey crops the next year112. Colonies are reported to have problems storing winter feed during Apilife VAR autumn treatment67.

ADVERCE EFFECT CAUSED BY ORGANIC ACIDS

FORMIC ACID LACTIC ACID OXALIC ACID

FORMIC ACID ADVERSE EFFECTS

Use of Formic acid gel resulted in removed drone eggs, delayed drone production and reduced adult drone survival (24% survival at 10 days old vrs. 49% for controls). Unlike fluvalinate, formic acid did not reduce drone weight or weight of glands Surviving drones had higher levels of sperm than controls33. Formic acid may also have adverse effects on open brood and hatching bees, depending on ambient temperature and device used, although loss of brood did not have a negative effect on colony overwintering in mid-European conditions92. Formic acid produced the highest rate of adult bee mortality (35.3 bees/hive/day) of 6 substances tested52. .

LACTIC ACID ADVERSE EFFECT

Lactic acid sprayed on combs at 8ml/dose caused bees to remove 60% of eggs86. In another experiment, bee mortality increased 4-fold for 2 days following treatment, but then returned to normal84. However, this may have been related to poor dosage control, since a precise dosage did not produce any adverse effects significantly different than coumaphos treatment, either in the autumn or the next spring87. Bee mortality was much lower for lactic acid (1.1 bee/hive/day) compared to formic acid (35.3 bees/hive/day)55.

OXALIC ACID ADVERSE EFFECT

Long term (4) spray applications of 3% oxalic acid in autumn and spring showed significantly negative effects on brood development and queen survival62, although other studies did not show such effects114; 19. Trials also suggest that some hives show adverse effects from oxalic acid syrup treatment29.

The results indicate that OA has a low acute toxicity to honey bees and a high

acute toxicity to mites. Alliano et al. 2006

OA is extensively used withoutknowing the basic toxicological

properties of the compoundto V. destructor or A. mellifera.

The results indicate that OA has a low acute toxicity to honey bees and a high

acute toxicity to mites.

Alliano et al. 2006

BY THE WAY

QUALITY OF HONEY

QUALITY OF HONEY DERRIVATE OF COMBCONTAMINATION

Council Regulation 2377/90 lays down a Community procedure to harmonise MRLs among Member States As a consequence of the Regulation the following restrictions are imposed on the production of honey:

An MRL is the maximum concentration of residue following administration of a veterinary medicine which is legally permitted or acceptable in food under the laws of the EU.

Annex I: Final MRLsThe data in the dossier are considered adequate to establish a final MRL.(amitraz, cymiazol, coumaphos)

Annex II: MRLs not necessaryThe data in the dossier demonstrate that there is no risk to the consumer and MRLs are not needed. (camphore, flumethryne, fluvalinate oxalicAcid, formic acid, thymol

Annex III: Provisional MRLsThis is for medicines where MRLs can be established but some clarification of further studies are required before final MRLs can be set. Annex IVResidues of the medicine pose an unacceptable risk to the consumer or there is insufficient information to allow a full assessment. The products in Annex IV are prohibited for use in food producing animals in the European Union.

EU REGULATIONS

• For honey MRLs have been fixed for coumaphos and amitraz, which are allowed in honey up to a limit of 100 and 200 parts per billion (ppb) respectively. This means that these substances are allowed to be present in honey, as long as the concentrations remain below these limits (see also Annex I of the Regulation).• Provisional MRLs for pharmacologically active substances used in veterinary medicinalproducts. For these residues there are no grounds for supposing that residues at the level proposed present a health hazard for the consumer. In the case of honey it concerns only cymiazole which is allowed to be present in honey up to a limit of 1000 ppb (see also Annex III of the Regulation).

Commission’s decision, made on Dec. 9 and 10, 2003 in London, which included oxalic acid for use with bees in Annex II of the Council Regulation (EEC) 2377/90 (as was already the case for formic acid, lactic acid and thymol). That means that no maximum limit exists for oxalic However, this does not mean that beekeepers are allowed to use an inappropriate amount of oxalic acid in treating their bees, thereby causing high amounts of residue in their honey. According to European honey standards, honey may have up to 50 milliequivalents of free acids. If higher residues of oxalic or other acids are produced, this limit is soon exceeded, and the beekeeper risks having problems if his honey is checked by authorities. If oxalic acid is used properly, there is absolutely no risk of problems with the honey.

OXALIC ACID AND OTHER ORGANIC ACIDS

RESISTANCE“the ability of an organism to tolerate toxic doses of a

substance that would be lethal to the majority of individuals in a normal population of the same species”

(Watkins 1996).

In effect, resistant mites are selected for, at the same time the susceptible ones are being selected

against (Eischen 1995)).

This resistance (to a pesticides for example) is genetically transmitted to offspring from the parents and

is not generated spontaneously as a chemical treatment is applied, the characteristic already exists in

the population (Eischen 1995).

Miticide Country Authors

A Amitraz Serbia Duijn et al. (1991)

B Amitraz USA Elzen et al. (1999,2000)

A Cumaphos Italy Spreafico et al. (2001)

B Cumaphos USA Pettis (2004).

A Fluvalinate / Flumethrine

Italy Milani (1993)

B Fluvalinate / Flumethrine

USA Elzen et al. (1999)

First cases of varroa* resistance tomost popular acaricides found in

Europe and north America

HOW TO HANDLE WITH THE VARROA PROBLEM

IN THE FIELD – IN GENERAL

IN HEAVILY INFESTED AREAS(huge winter deaths)

IN SLIGHTLY INFESTED AREAS(Normal winter deaths)

THE MOST IMPORTANT IS PRECISE KNOWLEDGE OF THE: 1 - LEVEL OF RESISTANCE TO USED SYNTHETIC ACARICIDES (ptretroids, amitraz)2 – THE NUMBER OF VARROA LEFT ON BEES AFTER THE TREATMENT

Laboratory trial for pyrethroide resistance – obligatory

Laboratory trial for pyrethroide resistance – not obligatory

MODE OF ACTION1 - High risk of resistance or full resistence - Hive Clean VERY USEFULL + ban on nucs 2 - No resistance – all official medicines allowed. Hovewer type of medicine indicates the manner of combat with varroa.3 – Movement into heavilly infested areas – in each case use of Hive Clean especially during fall change of bee generation – e.g. late buckweet.

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