https://biblio.ugent.be/publication/1076061/file/1076072.pdf

Acaricide resistance mechanisms in the two-spotted spider mite Tetranychus urticae and other important Acari: A review

The hive of the honey bee is a suitable habitat for diverse mites (Acari), including nonparasitic, omnivorous, and pollen-feeding species, and para- sites. The biology and damage of the three main pest species Acarapis woodi, Varroa jacobsoni, and Tropilaelaps clareae is reviewed, along with detection and control methods. The hypothesis that Acarapis woodiis a recently evolved species is rejected. Mite-associated bee pathologies (mostly viral) also cause increasing losses to apiaries. Future studies on bee mites are beset by three main problems: (a) The recent discovery of several new honey bee species and new bee-parasitizing mite species (along with the probability that several species are masquerading under the name Varroa jacob- soni) may bring about new bee-mite associations and increase damage to beekeeping; (b) methods for studying bee pathologies caused by viruses are still largely lacking; (c) few bee- and consumer-friendly methods for controlling bee mites in large apiaries are available.

/pdf/parasitic-mites-of-honey-bees-life-history-implications-and-4a436atm15.pdf

Parasitic mites of honey bees: life history, implications, and impact.

A field-collected strain (MR-VL) of the two-spotted spider mite, Tetranychus urticae Koch, exhibited strong resistance to bifenthrin, dicofol and fenbutatin oxide in comparison with a susceptible laboratory strain (LS-VL). The MR-VL strain was screened for cross-resistance with several currently used acaricides. Cross-resistance was detected with clofentezine (RR = 2631), dimethoate (RR = 250), chlorfenapyr (RR = 154), bromopropylate (RR = 25), amitraz (RR = 17), flucycloxuron (RR = 15) and azocyclotin (RR = 7). Abamectin, acequinocyl, bifenazate, tebufenpyrad and spirodiclofen did not show any signs of cross-resistance. Enhanced detoxification by increased activity of mono-oxygenases (MO) and esterases is at least partially responsible for the observed resistance and cross-resistance. MO assays with 7-ethoxycoumarin (7-EC) were optimised and 7-ethoxy-4-trifluoromethylcoumarin (7-EFC), a new MO-substrate, was evaluated for the first time in T urticae and proved to be a good alternative to 7-EC. Approximately 3- and 4-fold higher MO activity was detected with 7-EFC and 7-EC respectively in the MR-VL strain. Kinetic parameters of general esterase assays with 4-nitrophenyl acetate and 1-naphthyl acetate as substrate indicated that more esterases were present in the MR-VL strain. A first attempt was made to classify the esterases present in T urticae. Acetyl-, aryl- and carboxyl-esterases were detected with the use of inhibitors after separation by native PAGE. Glutathione-S-transferases did not seem to play any role in the observed resistance and no differences were detected when the general oxidative capacities of the two strains were compared.

Comparative acaricide susceptibility and detoxifying enzyme activities in field‐collected resistant and susceptible strains of Tetranychus urticae

Honey bees, Apis mellifera L., often thought to be extremely susceptible to insecticides in general, exhibit considerable variation in tolerance to pyrethroid insecticides. Although some pyrethroids, such as cyfluthrin and lambda-cyhalothrin, are highly toxic to honey bees, the toxicity of tau-fluvalinate is low enough to warrant its use to control parasitic mites inside honey bee colonies. Metabolic insecticide resistance in other insects is mediated by three major groups of detoxifying enzymes: the cytochrome P450 monooxygenases (P450s), the carboxylesterases (COEs), and the glutathione S-transferases (GSTs). To test the role of metabolic detoxification in mediating the relatively low toxicity of tau-fluvalinate compared with more toxic pyrethroid insecticides, we examined the effects of piperonyl butoxide (PBO), S,S,S-tributylphosphorotrithioate (DEF), and diethyl maleate (DEM) on the toxicity of these pyrethroids. The toxicity of the three pyrethroids to bees was greatly synergized by the P450 inhibitor PBO and synergized at low levels by the carboxylesterase inhibitor DEF. Little synergism was observed with DEM. These results suggest that metabolic detoxification, especially that mediated by P450s, contributes significantly to honey bee tolerance of pyrethroid insecticides. The potent synergism between tau-fluvalinate and PBO suggests that P450s are especially important in the detoxification of this pyrethroid and explains the ability of honey bees to tolerate its presence.

https://bioone.org/journals/journal-of-economic-entomology/volume-99/issue-4/0022-0493-99.4.1046/Mediation-of-Pyrethroid-Insecticide-Toxicity-to-Honey-Bees-Hymenoptera/10.1603/0022-0493-99.4.1046.pdf

Mediation of Pyrethroid Insecticide Toxicity to Honey Bees (Hymenoptera: Apidae) by Cytochrome P450 Monooxygenases

The mite Varroa destructor is an obligatory ectoparasite of the honey bee (Apis mellifera) and is one of the major threats to apiculture worldwide. We previously reported that honey bees fed on double-stranded RNA (dsRNA) with a sequence homologous to that of the Israeli acute paralysis virus are protected from the viral disease. Here we show that dsRNA ingested by bees is transferred to the Varroa mite and from mite on to a parasitized bee. This cross-species, reciprocal exchange of dsRNA between bee and Varroa engendered targeted gene silencing in the latter, and resulted in an over 60% decrease in the mite population. Thus, transfer of gene-silencing-triggering molecules between this invertebrate host and its ectoparasite could lead to a conceptually novel approach to Varroa control.

/pdf/bidirectional-transfer-of-rnai-between-honey-bee-and-varroa-v2j5awm4jm.pdf

Bidirectional transfer of RNAi between honey bee and Varroa destructor: Varroa gene silencing reduces Varroa population.

The aim of this study was to explore the extent of varroa mite resistance to fluvalinate in Israel and to determine the underlying biochemical mechanism. Assays at different apiaries indicated varroa mite resistance at three of the five sites tested. Dose response assays conducted with tau-fluvalinate on mites obtained from different sites indicated uneven resistance. A monooxygenase assay revealed an increased rate (approximately 20-fold) of activity in mites that were not controlled by the pesticide, as compared to activity in mites from untreated colonies. A minor, 1.5–2.5 fold, increase of esterase activity was also noted in the resistant mites. This first demonstration of a fluvalinate-resistance mechanism in varroa mites points to the need for more vigorous resistance management practices to control the pest.

First detection in Israel of fluvalinate resistance in the varroa mite using bioassay and biochemical methods.

Infestations by honey bee tracheal mite, Acarapis woodi (Rennie) (HBTM), were followed in three groups for one year. The groups consisted of 1) acaricide (amitraz) treated Italian bee colonies, 2) untreated Italian bee colonies, and 3) untreated Buckfast colonies. Mite prevalence of Buckfast bees declined from 45% in December to 10% in April and remained low, and most queens persisted for the entire period. Furthermore, bee populations increased and honey yield was high in comparison to seasonal averages. HBTM prevalence in the treated Italian colonies remained low until July, with a large increase in bee populations and honey yield, similar to that of the Buckfast colonies; however only a quarter of the queens survived. The untreated colonies were severely infested by the mite and much reduced in population, produced little honey and most of their queens were replaced. Nosema infections and Varroa mite prevalence rates were similar in all treatments. Along with a documentation of HBTM damage and control, this is also the first demonstration of the resistance of Buckfast bees to A. woodi under Mediterranean conditions. INTRODUCTION T he honey bee tracheal mite, Acarapis woodi (Rennie) (HBTM) was recently found in Israel (Gerson et al, 1994). Our preliminary observations indicated that the mite causes considerable damage, as it does in North America (Eischen et al., 1989), but in contrast to results obtained in Europe (Bailey and Lee, 1959). Numbers of honey bee colonies decreased because of increased bee mortality, especially in winter and spring, and honey production was much reduced. An intensive control project initiated at that time showed that fumigation with the pesticide amitraz 'Beekeeping Division, Extension Service, Ministry of Agriculture, FOB 7054, Tel Aviv, Israel. 2Zerifin Breeding Apiary, ARS, The Volcani Center, FOB 6, Bet Dagan 50250, Israel. !Kimron Veterinary Institute, Bet Dagan 50250, Israel. 'Department of Entomology, Faculty of Agricultural , Food and Environmental Quality Sciences, Hebrew University, Rehovot 76100, Israel. could control the pest (Dag et al., 1997). Honey bees show a wide range of susceptibilities to HBTM infestations, and vulnerable as well as resistant strains can be selected under controlled breeding conditions (Page and Gary, 1990). 'Buckfast' strain of honey bees has been undergoing selection since 1917 in England, and is credited with possessing a comparatively elevated level of resistance to HBTM without affecting bee productivity (Brother Adam, 1987; Lin et al, 1996). The aims of the present study were to quantify the rate of HBTM infestation and damage to a local Italian strain and to the Buckfast strain. MATERIALS AND METHODS An apiary containing 30 colonies, all heavily infested with HBTM, was established near Bet Dagan (coastal plain) in December 1996. The colonies were divided into three treatment groups of equal adult populations (5.5 populated frames). Colonies were provided either with Italian queens ('Zrifin, Central Breeding Apiary', n=20) or with Buckfast queens ['Paz Breeding Apiary', originating from a Buckfast breeding apiary in Luxembourg (stock B182), n=10]. Ten of the Italian colonies were fumigated three times with amitraz (for methodology, see Dag et al., 1997) in early December, before introducing the queens, whereas all other colonies were left untreated. All queens were mated naturally in an isolated area with drones from same-strain colonies. All queens were marked by clipping one of their wings and with painting their dorsal thoraces. Samples of ca 200 bees were collected from the outer populated combs of these colonies at monthly intervals; two samples were taken during the spring months (March-April). Collected bees were kept at -18°C until examined. The thoraces of 35 bees in each subset were dissected, their thoracic disks cleared in 2M NaOH (Shimanuki and Knox, 1991) and examined for tracheal mites. Results were calculated as rates of infested bees per colony on each sampling date. Adult bee populations were collected monthly and colonies were carefully examined for brood disease. Honey yield was recorded during the spring and summer harvests. The colonies were examined for the presence of the original queens in December 1997, a year after the trial was started. In order to reduce the effects of other common bee pests, all colonies were

Y. Kamer

Papers

First detection in Israel of fluvalinate resistance in the varroa mite using bioassay and biochemical methods.

The effect of honey bee tracheal mite infestation on colony development and honey yield of Buckfast and Italian honey bee strains in Israel.

Control of honey bee tracheal mite infestations with amitraz fumigation in Israel