Showing papers on "Varroa sensitive hygiene published in 2008"
TL;DR: The residues from Varroacide applications which are detectable today are all below the permitted maximum values, and they must be avoided in bee products, as honey possesses a very positive image in the mind of consumers.
Abstract: Varroosis is the most destructive disease of honey bees worldwide, inflicting much greater damage and higher economic costs than all other known apicultural diseases The disease pattern of Varroosis is not uniform, as both the rate of infestation and secondary infections determine the clinical symptoms Brood and adults bees are impaired The mite injures the bee through repeated intake of hemolymph with her chelicerae while the host is in the larval, pupal and adult stage The loss of hemolymph negatively effects the organ development of the bee Colonies infested by V destructor develop the parasitic mite syndrome and ultimately collapse if left untreated Favourable reproduction conditions in the new host A mellifera, the increasing impact of secondary infections (viruses) and the lack of coordinated and comprehensive treatment strategies and control methods that are often implemented too late or unsuccessfully by the beekeeper result in reappearing wide spread colony losses A viral infection vectored by V destructor obviously increases its impact on colony collapses with the cause of this ongoing crisis Varroa control should be a natural part of a beekeeper’s operation and flow into a system of Varroa control The residues from Varroacide applications which are detectable today are all below the permitted maximum values Although these minor detectable residues pose no threat to the consumer, they must be avoided in bee products, as honey possesses a very positive image in the mind of consumers
242 citations
TL;DR: Differences in behavior, rather than in the immune system, underlie Varroa tolerance in honey bees, and provide a first step toward better understanding molecular pathways involved in this important host-parasite relationship.
Abstract: The parasitic mite, Varroa destructor, is the most serious pest of the western honey bee, Apis mellifera, and has caused the death of millions of colonies worldwide. This mite reproduces in brood cells and parasitizes immature and adult bees. We investigated whether Varroa infestation induces changes in Apis mellifera gene expression, and whether there are genotypic differences that affect gene expression relevant to the bee's tolerance, as first steps toward unravelling mechanisms of host response and differences in susceptibility to Varroa parasitism. We explored the transcriptional response to mite parasitism in two genetic stocks of A. mellifera which differ in susceptibility to Varroa, comparing parasitized and non-parasitized full-sister pupae from both stocks. Bee expression profiles were analyzed using microarrays derived from honey bee ESTs whose annotation has recently been enhanced by results from the honey bee genome sequence. We measured differences in gene expression in two colonies of Varroa-susceptible and two colonies of Varroa-tolerant bees. We identified a set of 148 genes with significantly different patterns of expression: 32 varied with the presence of Varroa, 116 varied with bee genotype, and 2 with both. Varroa parasitism caused changes in the expression of genes related to embryonic development, cell metabolism and immunity. Bees tolerant to Varroa were mainly characterized by differences in the expression of genes regulating neuronal development, neuronal sensitivity and olfaction. Differences in olfaction and sensitivity to stimuli are two parameters that could, at least in part, account for bee tolerance to Varroa; differences in olfaction may be related to increased grooming and hygienic behavior, important behaviors known to be involved in Varroa tolerance. These results suggest that differences in behavior, rather than in the immune system, underlie Varroa tolerance in honey bees, and give an indication of the specific physiological changes found in parasitized bees. They provide a first step toward better understanding molecular pathways involved in this important host-parasite relationship.
199 citations
TL;DR: The results show that Bt Cry proteins used in genetically modified crops commercialized for control of lepidopteran and coleopteran pests do not negatively affect the survival of either honey bee larvae or adults in laboratory settings.
Abstract: Background
Honey bees (Apis mellifera L.) are the most important pollinators of many agricultural crops worldwide and are a key test species used in the tiered safety assessment of genetically engineered insect-resistant crops. There is concern that widespread planting of these transgenic crops could harm honey bee populations.
Methodology/Principal Findings
We conducted a meta-analysis of 25 studies that independently assessed potential effects of Bt Cry proteins on honey bee survival (or mortality). Our results show that Bt Cry proteins used in genetically modified crops commercialized for control of lepidopteran and coleopteran pests do not negatively affect the survival of either honey bee larvae or adults in laboratory settings.
Conclusions/Significance
Although the additional stresses that honey bees face in the field could, in principle, modify their susceptibility to Cry proteins or lead to indirect effects, our findings support safety assessments that have not detected any direct negative effects of Bt crops for this vital insect pollinator.
175 citations
TL;DR: Results showed relative effectiveness of high- and low-grooming groups being affected by the environment, and differences in grooming between lines were greatest at 25 °C and were slightly higher under conditions of low humidity than at higher levels.
Abstract: This study assessed how variation in temperature and humidity affect the costs and benefits of grooming as a defense against Varroa destructor Anderson and Trueman, 2000 in high-grooming and low-grooming groups of honey bee (Apis mellifera L., 1758) workers. Grooming was quantified as the proportion of mites falling to the bottom of cages containing worker bees or to the bottom of colonies of bees during winter. Cages of 100 mite-infested bees from each line of workers were assigned to environments with three treatment combinations of temperature (10, 25, and 34 °C) and humidity (low, medium, and high), and bee and mite mortality rates were quantified. The results showed relative effectiveness of high- and low-grooming groups being affected by the environment. Differences in grooming between lines were greatest at 25 °C and were slightly higher under conditions of low humidity than at higher levels. Mite mortality rates were greater in high-grooming groups of caged bees than in low-grooming bees held at 2...
64 citations
TL;DR: resistant stocks of USDA-developed Russian and varroa sensitive hygiene honey bees have good potential for use in nonmigratory beekeeping operations in the southeastern United States.
Abstract: The utility of USDA-developed Russian and varroa sensitive hygiene (VSH) honey bees, Apis mellifera L. (Hymenoptera: Apidae), was compared with that of locally produced, commercial Italian bees during 2004–2006 in beekeeping operations in Alabama, USA. Infestations of varroa mites, Varroa destructor Anderson & Truman (Acari: Varroidae), were measured twice each year, and colonies that reached established economic treatment thresholds (one mite per 100 adult bees in late winter; 5–10 mites per 100 adult bees in late summer) were treated with acaricides. Infestations of tracheal mites, Acarapis woodi (Rennie) (Acari: Tarsonemidae), were measured autumn and compared with a treatment threshold of 20% mite prevalence. Honey production was measured in 2005 and 2006 for colonies that retained original test queens. Throughout the three seasons of measurement, resistant stocks required less treatment against parasitic mites than the Italian stock. The total percentages of colonies needing treatment against varroa mites were 12% of VSH, 24% of Russian, and 40% of Italian. The total percentages requiring treatment against tracheal mites were 1% of Russian, 8% of VSH and 12% of Italian. The average honey yield of Russian and VSH colonies was comparable with that of Italian colonies each year. Beekeepers did not report any significant behavioral problems with the resistant stocks. These stocks thus have good potential for use in nonmigratory beekeeping operations in the southeastern United States.
39 citations
TL;DR: The results suggest that mite populations in VSH colonies could increase more rapidly when drone brood is available, and the rate of uncapping brood by hygienic bees may depend on the infestation rate, which gradually decreases with longer exposures to bees that remove mite-infested pupae from capped brood.
Abstract: Honey bees (Apis mellifera L.) (Hymenoptera: Apidae) have been selectively bred for varroa-sensitive hygiene (VSH), which is the removal of pupae that are infested by Varroa destructor Anderson & Trueman from capped brood cells. This hygienic behavior is a complex interaction of bees and brood in which brood cells are inspected, and then brood is either removed or recapped. Previous work has shown that VSH bees uncap and remove significantly more varroa-infested worker pupae than nonhygienic bees do, but nothing is known about the reactions of VSH bees to mite-infested drone brood. This study compared the reactions of VSH bees with mite-infested worker and drone brood in a laboratory test and a field test. VSH bees inspected brood cells containing mite-infested pupae of both types of brood, but they removed significantly fewer mite-infested drone pupae than mite-infested worker pupae after 1 wk. This result suggests that mite populations in VSH colonies could increase more rapidly when drone brood is available. Additionally, the percentages of uncapped pupae and uncapped mite-infested pupae were positively correlated to the natural infestation rate of brood after a 24-h exposure, but not after an exposure of 1 wk. This result suggests that the rate of uncapping brood by hygienic bees may depend on the infestation rate, which gradually decreases with longer exposures to bees that remove mite-infested pupae from capped brood.
28 citations
TL;DR: The short-term formic acid treatment killed >60% of varroa mites in capped worker brood and on adult bees without harming queens or uncapped brood; thus, it is a promising tool for beekeepers, especially when such treatments are necessary during the nectar flow.
Abstract: Controlling populations of varroa mites is crucial for the survival of the beekeeping industry. Many treatments exist, and all are designed to kill mites on adult bees. Because the majority of mites are found under capped brood, most treatments are designed to deliver active ingredients over an extended period to control mites on adult bees, as developing bees and mites emerge. In this study, a 17-h application of 50% formic acid effectively killed mites in capped worker brood and on adult bees without harming queens or uncapped brood. Neither acetic acid nor a combined treatment of formic and acetic acids applied to the West Virginia formic acid fumigator was as effective as formic acid alone in controlling varroa mites. In addition, none of the treatments tested in late summer had an effect on the late-season prevalence of deformed wing virus. The short-term formic acid treatment killed >60% of varroa mites in capped worker brood; thus, it is a promising tool for beekeepers, especially when such treatments are necessary during the nectar flow.
23 citations
TL;DR: Considering the observed variability among honey bee packages, beekeepers should be aware of the potential for pest and disease infestations and high drone levels in packages.
Abstract: To replace deceased colonies or to increase the colony numbers, beekeepers often purchase honey bees, Apis mellifera L., in a package, which is composed of 909–1,364 g (2–3 lb) of worker bees and a mated queen. Packages are typically produced in warm regions of the United States in spring and shipped throughout the United States to replace colonies that perished during winter. Although the package bee industry is effective in replacing colonies lost in winter, packages also can be an effective means of dispersing diseases, parasites, and undesirable stock to beekeepers throughout the United States. To evaluate the quality of packages, we examined 48 packages representing six lines of bees purchased in the spring 2006. We estimated levels of the parasitic mite Varroa destructor Anderson & Trueman and the percentage of drone (male) honey bees received in packages. We surveyed for presence of the tracheal honey bee mite, Acarapis woodi (Rennie), and a microsporidian parasite, Nosema spp., in the shi...
6 citations
TL;DR: This study shows that indoor winter fumigation of A. mellifera colonies with formic acid lacks long term effects on queens, and whether a long-term “low” concentration or a short-term high concentration was used, surviving queens were as productive as untreated wintered queens.
Abstract: SummaryFormic acid fumigation has been used to control infestations of the varroa mite, Varroa destructor Anderson & Trueman, and the tracheal mite, Acarapis woodi (Rennie) in honey bee, Apis mellifera L., colonies in various situations. Studies on the use of formic acid have generally focused on the immediate, direct effects of treatment. However, the potential for long-term effects is also of concern to beekeepers. The obJective of this study was to determine whether indoor winter fumigation of A. mellifera colonies with formic acid affects long-term queen performance by measuring sealed brood production, the frequency of queen supersedure, and honey production.Two experiments, during which A. mellifera colonies were fumigated with formic acid in an indoor wintering facility, were conducted during the winter of 2001–2002. After V. destructor populations were reduced to equivalent levels and A. mellifera populations were equalized, colonies with their original queens were evaluated for brood and honey pr...
5 citations
TL;DR: It is highly likely that other factors, such as island climate, the lack of a continuous influx of Africanized bees, and the absence of Varroa mites, a common pest of European bees has allowed their survival.
Abstract: . The first evaluation of the feral population of honey bees on the island of St. Croix, US Virgin Islands is performed. Since Africanized bees had been reported in 1994, we expected that, as in the neighboring island of Puerto Rico, the feral population of St. Croix would be strongly Africanized. We sampled worker bees of 13 colonies. Using a molecular technique that distinguishes European from Africanized bees we found that nine sampled colonies were Africanized and four were European by maternal descent. The lack of a complete genetic sweep by Africanized bees contrasts greatly with the population in Puerto Rico and populations studied in the mainland. Even though the presence of European bees on the island may be due to input from the apicultural sector, it is highly likely that other factors, such as island climate, the lack of a continuous influx of Africanized bees, and the absence of Varroa mites, a common pest of European bees has allowed their survival.
01 Jan 2008
TL;DR: The results indicate that OA has a low acute toxicity to honey bees and a high acute toxicityTo establish a baseline for OA susceptibility for both parasite and host to compare with future populations if Varroa mites exhibit resistance to OA.
Abstract: I performed laboratory bioassays to characterize the acute contact toxicity of oxalic acid (OA) to Varroa destructor (Anderson & Trueman) and their honey bee hosts (Apis mellifera). Specifically, I conducted glass-vial residual bioassays to determine the lethal concentration of OA for Varroa, and I conducted topical applications of OA in acetone to determine the lethal dose for honey bees. The results indicate that OA has a low acute toxicity to honey bees and a high acute toxicity to mites. The toxicity data will help guide scientists in delivering optimum dosages of OA to the parasite and its host, and will be useful in making treatment recommendations. The data will also establish a baseline for OA susceptibility for both parasite and host to compare with future populations if Varroa mites exhibit resistance to OA. Introduction The objective of this study was to characterize the acute contact toxicity of OA to Varroa mites and their honey bee hosts in laboratory bioassays. Only one study has quantified the contact toxicity of OA to Varroa mites collected from brood cells (Milani 2001), and the contact toxicity of OA to honey bees has not been determined. One
Journal Article•
01 Jan 2008
Journal Article•
TL;DR: Tau-fluvalinate was mostly used and frequency of chemical use was estimated around six to ten per year, suggesting that bioassay kit testing is more cost-effective than the whole hive treatment.
Abstract: The varroa mite is now a serious threat for the beekeeping industry in the world. Because of the strict regulation of synthetic chemical residues in honeybee products, beekeepers are searching the safe way of pest management to minimize the use of chemicals. In this study, the efficacy of chemicals was tested against varroa mites. The efficacy of chemicals was compared by the whole hive and bioassay kit methods. Among the chemicals, tau-fluvalinate was most effective followed by amitraz and flumethrin. Coumaphos and flavonoid+citric acid showed lower efficacies in summer and fall treatment. Also among the environmentfriendly materials, formic acid and thymol showed the higher efficacies. From the results, it was suggesting that bioassay kit testing is more cost-effective than the whole hive treatment. From this history of beekeepers’ chemical uses, tau-fluvalinate was mostly used and frequency of chemical use was estimated around six to ten per year. Further research involvement in chemical efficacy testing was discussed.
01 Jan 2008
TL;DR: This study indicates that using mixture of essential oils was more suitable with cotton strips incontrolling Varroa mite, and genetic improvement by using hybrid queens between Apis mellifera carnica and Api lamerkii proved to be an effective and reliable method for the control of VarroA destructor.
Abstract: The efficacy of essential oils i.e. geranium oil, lemon oil, mint oil, chamomile oil and black cumin oil, used alone or inmixtures, compared with a chemical insecticide, mitac, against Varroa mite was evaluated. The infestation levels ofthese substances were evaluated in honeybee colonies during October, November and December 2005 in GizaGovernorate. Cotton strips, saturated with the tested substances, were hanged between the middle combs in alltreatments. The efficacy rate of geranium oil, lemon oil, mixture of (geranium, lemon, chamomile and mint oils) andmixture of (lemon, black cumin and mint oils), in comparison with mitac was 37.27%, 32.56%, 37.59%, 36.27% and53.64% respectively. This study indicates that using mixture of essential oils was more suitable with cotton strips incontrolling Varroa mite. Genetic improvement by using hybrid queens between Apis mellifera carnica (drones) andApis mellifera lamerkii (virgins), proved to be an effective and reliable method for the control of Varroa destructor.Cultural control by lemon oil or added to sugar solution was used in feeding the colonies, especially in winter. Puttingthe colonies in citrus garden and cultivation of geranium or chamomile around apiaries (these new cultural control)were added to IPM programmes for control Varroa mite.
01 Jan 2008
TL;DR: It is indicated that neem oil is not suitable against Egyptian race, genetic control by using the local Egyptian race Apis mellifera lamerckii and the cross-breeding between two geographicalraces resulting hybrid vigor could be an effective and reliable method for the control of Varroa destructor.
Abstract: During September-November 2006 in Giza Governorate mint oil, chamomile oil, neem oil and mixture of (neem, blackcumin and jasmine oils) compared with the chemical substance mavrik were tested for their efficacy in controlling thebee mite Varroa destructor on two stocks of Apis mellifera lamerkii. The efficacy rate in Egyptian race was 44.76%,66.64%, 4.95%, 52.88% and 89.54%, respectively, while in hybrid Egyptian carniolan was 64.75%, 41.08%, 61.7%,59.49% and 78.78%, respectively. This study indicates that neem oil is not suitable against Egyptian race, geneticcontrol by using the local Egyptian race Apis mellifera lamerckii and the cross-breeding between two geographicalraces resulting hybrid vigor could be an effective and reliable method for the control of Varroa destructor. Using mintoil and mixture of oils were also more suitable with cotton strips. Finally, the importance of cultivation of aromaticand medicinal plants around apiaries, as a cultural control, was recommended in IPM programmes to control Varroamite.