Evaluation of potential miticide toxicity to Varroa destructor and honey bees, Apis mellifera, under laboratory conditions

Bahreini, Rassol; Nasr, Medhat E.; Docherty, Cassandra; Herdt, Olivia de; Muirhead, Samantha; Feindel, David

doi:10.1038/s41598-020-78561-2

Cited by 23 publications

(61 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…They found three different cages with 20 mL plastic syringe feeders, with the addition of protein to feeding regimes, had the highest honey bee survivorship. More recently, the effect of miticides on honey bees was evaluated in 60 mL glass Mason jars [27]. In this method, a group of newly-emerged worker bees were contact-exposed to chemicals covering the inner surface of jars.…”

Section: Introductionmentioning

confidence: 99%

“…Bioassay techniques used for testing chemicals on mites and bees, more specifically, have mainly focused on determining the level of resistance of Varroa to currently available miticides. In these bioassays, techniques such as chemically coating the inner surface of vials or jars [27][28][29], small capsules covered with paraffin [30], chemically impregnated Parafilm wax [31] or plastic containers [13] have been used. For instance, Rinkevich [13] evaluated amitraz resistance in mite populations of some beekeeping operations in the USA using a 946 mL polypropylene plastic container.…”

Section: Introductionmentioning

confidence: 99%

“…According to Rinkevich [13], 100% Varroa mortality was evaluated in amitraz-susceptible mites in comparison to <80% in resistant populations. Only a few studies exist that are aimed at testing new synthetic chemicals for Varroa control [27,29,32]. Ali et al [32] treated honey bee colonies with tebufenpyrad and found a high efficacy for this compound.…”

Section: Introductionmentioning

confidence: 99%

“…Results indicated that Varroa had a higher susceptibility to Shuttle1 followed by Apollo1, Forbid1 and Flora-mite1. In a more recent study, Bahreini et al [27] also used the vial test to screen chemicals against mites and a Mason jar test for bee toxicity. Results showed that fenazaquin and etoxazole had high efficacy for Varroa control.…”

Section: Introductionmentioning

confidence: 99%

“…Results showed that fenazaquin and etoxazole had high efficacy for Varroa control. From these laboratory studies [27,29], high efficacy miticides need to be screened more thoroughly under field or colony-like conditions.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

New bioassay cage methodology for in vitro studies on Varroa destructor and Apis mellifera

Bahreini¹,

Nasr²,

Docherty³

et al. 2021

PLoS ONE

Self Cite

View full text Add to dashboard Cite

Varroa destructor Anderson and Trueman, is an ectoparasitic mite of honey bees, Apis mellifera L., that has been considered a major cause of colony losses. Synthetic miticides have been developed and registered to manage this ectoparasite, however, resistance to registered pyrethroid and organophosphate Varroacides have already been reported in Canada. To test toxicity of miticides, current contact-based bioassay methods are designed to evaluate mites and bees separately, however, these methods are unlikely to give an accurate depiction of how miticides interact at the colony level. Therefore, the objective of this study was to develop a bioassay cage for testing the toxicity of miticides on honey bees and Varroa mites simultaneously using amitraz as a reference chemical. A 800 mL polypropylene plastic cage holding 100–150 bees was designed and officially named “Apiarium”. A comparison of the effects of three subsequent dilutions of amitraz was conducted on: Varroa mites placed in glass vials, honey bees in glass Mason jars, and Varroa-infested bees in Apiariums. Our results indicated cumulative Varroa mortality was dose-dependent in the Apiarium after 4 h and 24 h assessments. Apiarium and glass vial treatments at 24 h also had high mite mortality and a positive polynomial regression between Varroa mortality and amitraz dose rates. Moreover, chemical application in the Apiarium was less toxic for bees compared to the Mason jar method. Considering these results, the Apiarium bioassay provides a simple, cheap and reliable method for simultaneous chemical screening on V. destructor and A. mellifera. Furthermore, as mites and bees are tested together, the Apiarium simulates a colony-like environment that provides a necessary bridge between laboratory bioassay testing and full field experimentation. The versatility of the Apiarium allows researchers to test a multitude of different honey bee bioassay experiments including miticide screening, delivery methods for chemical products, or development of new mite resistance-testing methodology.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

New bioassay cage methodology for in vitro studies on Varroa destructor and Apis mellifera

Bahreini¹,

Nasr²,

Docherty³

et al. 2021

PLoS ONE

Self Cite

View full text Add to dashboard Cite

show abstract

Testing new compounds for efficacy against Varroa destructor and safety to honey bees (Apis mellifera)

Jack

Kleckner

Démares

et al. 2021

Pest Management Science

View full text Add to dashboard Cite

BACKGROUND: Varroa destructor is among the greatest threats to honey bee health worldwide. Acaricides used to control Varroa are becoming increasingly ineffective due to resistance issues, prompting the need for new compounds that can be used for control purposes. Ideally, such compounds would exhibit high toxicity to Varroa while maintaining relatively low toxicity to bees and beekeepers. We characterized the lethal concentrations (LC 50 ) of amitraz, matrine, FlyNap®, the experimental carbamates 2-((2-ethylbutyl)thio)phenyl methylcarbamate (1) and 2-(2-ethylbutoxy)phenyl methylcarbamate (2), and dimethoate (positive control) for Varroa using a glass vial assay. The test compounds also were applied to honey bees using an acute contact toxicity assay to determine the adult bee LD 50 for each compound. RESULTS: Amitraz was the most toxic compound to Varroa, but carbamate 2 was nearly as active (within 2-fold) and the most selective due to its lower bee toxicity, demonstrating its promise as a Varroa control. While carbamate 1 was less toxic to honey bees than was amitraz, it was also 4.7-fold less toxic to the mites. Both matrine and FlyNap® were relatively ineffective at killing Varroa and were moderately toxic to honey bees. CONCLUSION: Additional testing is required to determine if carbamate 2 can be used as an effective Varroa control. As new chemical treatments are identified, it will be necessary to determine how they can be utilized best alongside other control techniques as part of an integrated pest management program.

show abstract

Miticidal activity of fenazaquin and fenpyroximate againstVarroa destructor, an ectoparasite ofApis mellifera

Bahreini¹,

Nasr²,

Docherty³

et al. 2022

Pest Management Science

Self Cite

View full text Add to dashboard Cite

BACKGROUND The Varroa mite (Varroa destructor) is an ectoparasite that can affect the health of honey bees (Apis mellifera) and contributes to the loss of colony productivity. The limited availability of Varroacides with different modes of action in Canada has resulted in the development of chemical resistance in mite populations. Therefore, an urgent need to evaluate new potential miticides that are safe for bees and exhibit high efficacy against Varroa exists. In this study, the acute contact toxicity of 26 active ingredients (19 chemical classes), already available on the market, was evaluated on V. destructor and A. mellifera under laboratory conditions using an apiarium bioassay. In this assay, groups of Varroa‐infested worker bees were exposed to different dilutions of candidate compounds. In semi‐field trials, Varroa‐infested honey bees were randomly treated with four vetted candidate compounds from the apiarium assay in mini‐colonies. RESULTS Among tested compounds, fenazaquin (quinazoline class) and fenpyroximate (pyrazole class) had higher mite mortality and lower bee mortality over a 24 h exposure period in apiariums. These two compounds, plus spirotetramat and spirodiclofen, were selected for semi‐field evaluation based on the findings of the apiarium bioassay trials and previous laboratory studies. Consistent with the apiarium bioassay, semi‐field results showed fenazaquin and fenpyroximate had high efficacy (>80%), reducing Varroa abundance by 80% and 68%, respectively. CONCLUSION These findings suggest that fenazaquin would be an effective Varroacide, along with fenpyroximate, which was previously registered for in‐hive use as Hivastan. Both compounds have the potential to provide beekeepers with an alternative option for managing Varroa mites in honey bee colonies. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

show abstract

Evaluation of potential miticide toxicity to Varroa destructor and honey bees, Apis mellifera, under laboratory conditions

Cited by 23 publications

References 47 publications

New bioassay cage methodology for in vitro studies on Varroa destructor and Apis mellifera

New bioassay cage methodology for in vitro studies on Varroa destructor and Apis mellifera

Testing new compounds for efficacy against Varroa destructor and safety to honey bees (Apis mellifera)

Miticidal activity of fenazaquin and fenpyroximate againstVarroa destructor, an ectoparasite ofApis mellifera

Contact Info

Product

Resources

About