Bee Mortality Research Articles

Belgian honey bee winter mortality during 2012-2013: a case-control study and spatial analysis

An increase in honey bee mortality has been reported within and outside the European Union. A Belgian honey bee health monitoring was started in 2012 based on a standardized and pan-European voluntary surveillance program (EPILOBEE). The main objective was to estimate honey bee mortality during winter and the apicultural season using a harmonized survey. For the Belgian study, the guidelines were adapted according to small-scale Belgian beekeeping practices and previous pathogen prevalence studies. A two-stage sampling stratified by province resulted in 150 apiaries selected from a sampling frame of approximately 3,000 registered beekeepers. These apiaries were visited twice, questionnaires were completed, collecting information on risk factors and mortality. Samples systematically taken in autumn were screened / quantified for Varroa destructor mites. Weighted colony winter mortality rates were estimated per individual apiary and for geographical entities. We then attempted to identify risk factors in a case-control data interpretation, with observed mortality as a binary dependent variable. Questionnaire variables were evaluated in univariable logistic regression. The final multivariable model was retained: age of beekeeper, wanting to continue beekeeping, increasing number of surrounding landscapes, average colony varroa infestation level, all associated with increased mortality. Chemical acaricide treatment before 1 September and Thymol-containing acaricide were associated with lower mortality. The predictive accuracy of this final model was estimated by the area under the curve (AUC) and was 80.70%. The final predicted mortality risk was visualized on a map as an interpolated layer and compared with the observed mortality; clusters of high/low mortality were identified. This analysis has generated further hypotheses and highlighted where the case-control study could benefit from increased sample size.

Effectiveness of Treatments with Thymol in Controlling Varroa Destructor Parasite of The Honey Bee in Algeria

Varroa disease is a parasitic disease of adult bees and brood, due to a blood-sucking external parasitic mite, Varroa destructor. This is one of the most dangerous diseases in Algeria. The purpose of this study is to evaluate the effectiveness of two treatments approved based thymol (Thymovar® and Apiguard®) in the fight against varroa in Algerian conditions and to determine the side effects of these treatments on bee colonies local Apis mellifera intermissa. The test was performed on 80 colonies with two different formulations for each treatment. As the results show in our test, a wide variation in the effectiveness between colonies is recorded for both treatments. The average efficiency for the group of colonies ½ Thymovar strap in two applications stood at 84.43%. This efficiency is lower for the group ½ straps in one application (77.23%). For Apiguard, the average efficiency is 81% for formulation 2 x 25g spaced two weeks, against a 79% rate for the formulation of 2X25 spaced one week. During our tests, with a few dead bees and nymphs found on nappies, we never recorded unusually high bee mortality. Further tests are needed to determine the optimal dose and the best time for treatment.

The effect of dicyclohexylamine and fumagillin on Nosema ceranae-infected honey bee (Apis mellifera) mortality in cage trial assays

Both commercially available fumagillin-based treatments for honey bees (Apis mellifera), Fumagilin-B® as well as Fumidil-B®, contain the reportedly genotoxic and tumorigenic compound dicyclohexylamine (DCH) as the counter ion in the fumagillin-DCH salt. The effect of DCH, purified fumagillin (containing no DCH), and the commercial formulation Fumagilin-B® (containing both fumagillin as well as DCH) on the mortality of caged Nosema ceranae-infected honey bees was investigated. A statistically significant risk of bee mortality associated with oral exposure to DCH was observed. DCH is also known to be significantly more stable than fumagillin in honey under a variety of temperature conditions, both in the presence and absence of light. The presence of DCH in the hive is therefore a potential concern for bee health and also for food safety.

Evaluation of Fumagilin-B® and other potential alternative chemotherapies against Nosema ceranae-infected honeybees (Apis mellifera) in cage trial assays

Fumagilin-B® is the only currently registered chemical treatment available to combat nosema disease in apiculture. Fumagillol, the basic hydrolysis product of fumagillin, two semisynthetic fumagillin analogues, and four in-house purely synthetic compounds which were designed to mimic the mode of action of fumagillin against the methionine aminopeptidase type 2 (MetAP-2) enzyme, was observed to exhibit statistically significant biological activity against Nosema ceranae-infected caged bees. None of these compounds were, however, as effective as Fumagilin-B®. The commercially available thymol and enilconazole also exhibited activity against N. ceranae, with thymol being the most promising chemical treatment other than Fumagilin-B®. High cumulative bee mortality was associated with the therapeutic dosage of Fumagilin-B® during our study, suggesting the need for continued investigation.

Nutritional Effect of Alpha-Linolenic Acid on Honey Bee Colony Development (Apis Mellifera L.)

Abstract Alpha-linolenic acid (ALA), which is an n-3 polyunsaturated fatty acid (PUFA), influences honey bee feed intake and longevity. The objective of this study was to research the effect of six dietary ALA levels on the growth and development of Apis mellifera ligustica colonies. In the early spring, a total of 36 honey bee colonies of equal size and queen quality were randomly allocated into 6 groups. The six groups of honey bees were fed a basal diet with supplementation of ALA levels at 0 (group A), 2 (group B), 4 (group C), 6 (group D), 8 (group E), and 10% (group F). In this study, there were significant effects of pollen substitute ALA levels on the feeding amounts of the bee colony, colony population, sealed brood amount, and weight of newly emerged workers (P<0.05). The workers’ midgut Lipase (LPS) activity of group C was significantly lower than that of the other groups (P<0.01). The worker bees in groups B, C, and D had significantly longer lifespans than those in the other groups (P<0.05). However, when the diets had ALA concentrations of more than 6%, the mortality of the honey bees increased (P<0.01). These results indicate that ALA levels of 2 ~ 4% of the pollen substitute were optimal for maintaining the highest reproductive performance and the digestion and absorption of fatty acids in honey bees during the period of spring multiplication. Additionally, ALA levels of 2 ~ 6% of the pollen substitute, improved worker bee longevity.

Outcome of the pesticides peer review meeting on general recurring issues in ecotoxicology

Outcome of the pesticides peer review meeting on general recurring issues in ecotoxicology

Predicting Honeybee Colony Failure: Using the BEEHAVE Model to Simulate Colony Responses to Pesticides.

To simulate effects of pesticides on different honeybee (Apis mellifera L.) life stages, we used the BEEHAVE model to explore how increased mortalities of larvae, in-hive workers, and foragers, as well as reduced egg-laying rate, could impact colony dynamics over multiple years. Stresses were applied for 30 days, both as multiples of the modeled control mortality and as set percentage daily mortalities to assess the sensitivity of the modeled colony both to small fluctuations in mortality and periods of low to very high daily mortality. These stresses simulate stylized exposure of the different life stages to nectar and pollen contaminated with pesticide for 30 days. Increasing adult bee mortality had a much greater impact on colony survival than mortality of bee larvae or reduction in egg laying rate. Importantly, the seasonal timing of the imposed mortality affected the magnitude of the impact at colony level. In line with the LD50, we propose a new index of “lethal imposed stress”: the LIS50 which indicates the level of stress on individuals that results in 50% colony mortality. This (or any LISx) is a comparative index for exploring the effects of different stressors at colony level in model simulations. While colony failure is not an acceptable protection goal, this index could be used to inform the setting of future regulatory protection goals.

Vertical diversity patterns and biotic interactions of trap-nesting bees along a fragmentation gradient of small secondary rainforest remnants

Secondary rainforest remnants might contribute to biodiversity conservation and preservation of healthy interspecific interactions with ongoing fragmentation. We studied the vertical distribution of trap-nesting bees along a fragmentation gradient of secondary forest remnants in Costa Rica. Fragment size did not affect bee abundance, diversity, and parasitism and mortality rates. However, height and edge effects influenced bee communities. Bees were more abundant in the canopy and the understory compared to an intermediate height, and bee diversity was higher in the canopy. Tree location (forest edge, intermediate distance, forest center) did not affect abundance but did affect bee diversity since most species preferred the forest interior. The cuckoo bees Aglaomelissa duckei and Coelioxys sp. 1 only partly followed their hosts’ patterns, two Centris species. We conclude that an increasing amount of edge habitat will have negative consequences for bee communities and will reduce the conservation value of secondary forest fragments.

Prochloraz and coumaphos induce different gene expression patterns in three developmental stages of the Carniolan honey bee (Apis mellifera carnica Pollmann)

The Carniolan honey bee, Apis mellifera carnica, is a Slovenian autochthonous subspecies of honey bee. In recent years, the country has recorded an annual loss of bee colonies through mortality of up to 35%. One possible reason for such high mortality could be the exposure of honey bees to xenobiotic residues that have been found in honey bee and beehive products. Acaricides are applied by beekeepers to control varroosis, while the most abundant common agricultural chemicals found in honey bee and beehive products are fungicides, which may enter the system when applied to nearby flowering crops and fruit plants. Acaricides and fungicides are not intrinsically highly toxic to bees but their action in combination might lead to higher honey bee sensitivity or mortality. In the present study we investigated the molecular immune response of honey bee workers at different developmental stages (prepupa, white-eyed pupa, adult) exposed to the acaricide coumaphos and the fungicide prochloraz individually and in combination. Expression of 17 immune-related genes was examined by quantitative RT-PCR. In treated prepupae downregulation of most immune-related genes was observed in all treatments, while in adults upregulation of most of the genes was recorded. Our study shows for the first time that negative impacts of prochloraz and a combination of coumaphos and prochloraz differ among the different developmental stages of honey bees. The main effect of the xenobiotic combination was found to be upregulation of the antimicrobial peptide genes abaecin and defensin-1 in adult honey bees. Changes in immune-related gene expression could result in depressed immunity of honey bees and their increased susceptibility to various pathogens.

Are commercial probiotics and prebiotics effective in the treatment and prevention of honeybee nosemosis C?

The study was conducted to investigate the effect of Lactobacillus rhamnosus (a commercial probiotic) and inulin (a prebiotic) on the survival rates of honeybees infected and uninfected with Nosema ceranae, the level of phenoloxidase (PO) activity, the course of nosemosis, and the effect on the prevention of nosemosis development in bees. The cells of L. rhamnosus exhibited a high rate of survival in 56.56 % sugar syrup, which was used to feed the honeybees. Surprisingly, honeybees fed with sugar syrup supplemented with a commercial probiotic and a probiotic + prebiotic were more susceptible to N. ceranae infection, and their lifespan was much shorter. The number of microsporidian spores in the honeybees fed for 9 days prior to N. ceranae infection with a sugar syrup supplemented with a commercial probiotic was 25 times higher (970 million spores per one honeybee) than in a control group fed with pure sucrose syrup (38 million spores per one honeybee). PO activity reached its highest level in the hemolymph of this honeybee control group uninfected with N. ceranae. The addition of probiotics or both probiotics and prebiotics to the food of uninfected bees led to the ~2-fold decrease in the PO activity. The infection of honeybees with N. ceranae accompanied an almost 20-fold decrease in the PO level. The inulin supplemented solely at a concentration of 2 μg/mL was the only administrated factor which did not significantly affect honeybees’ survival, the PO activity, or the nosemosis infection level. In conclusion, the supplementation of honeybees’ diet with improperly selected probiotics or both probiotics and prebiotics does not prevent nosemosis development, can de-regulate insect immune systems, and may significantly increase bee mortality.

Influence of pesticide use in fruit orchards during blooming on honeybee mortality in 4 experimental apiaries

Samples of dead honey bees (Apis mellifera L.) were collected periodically from 4 different locations during citrus and stone fruit trees blooming season to evaluate the potential impact of agrochemicals on honey bee death rate. For the determination of mortality, dead honey bee traps were placed in front of the experimental hives entrance located in areas of intensive agriculture in Valencian Community (Spain). A total of 34 bee samples, obtained along the monitoring period, were analyzed by means of QuEChERS extraction method and screened for 58 pesticides or their degradation products by LC–MS/MS. An average of four pesticides per honey bee sample was detected. Coumaphos, an organophosphate acaricide used against varroosis in the experimental hives, was detected in 94% of the samples. However, this acaricide was unlikely to be responsible for honey bee mortality because its constantly low concentration during all the monitoring period, even before and after acute mortality episodes. The organophosphates chlorpyrifos and dimethoate, as well as the neonicotinoid imidacloprid, were the most frequently detected agrochemicals. Almost 80% of the samples had chlorpyrifos, 68% dimethoate, and 32% imidacloprid. Maximum concentrations for these three compounds were 751, 403, 223ng/g respectively. Influence of these pesticides on acute honey bee mortality was demonstrated by comparing coincidence between death rate and concentrations of chlorpyrifos, dimethoate and imidacloprid.

The influence of Nosema (Microspora: Nosematidae) infection on honey bee (Hymenoptera: Apidae) defense against Varroa destructor (Mesostigmata: Varroidae)

The objectives of this study were to quantify the costs and benefits of co-parasitism with Varroa (Varroa destructor Anderson and Trueman) and Nosema (Nosema ceranae Fries and Nosema apis Zander) on honey bees (Apis mellifera L.) with different defense levels. Newly-emerged worker bees from either high-mite-mortality-rate (high-MMR) bees or low-mite-mortality-rate (low-MMR) bees were confined in forty bioassay cages which were either inoculated with Nosema spores [Nosema (+) group] or were left un-inoculated [Nosema (−) group]. Caged-bees were then inoculated with Varroa mites [Varroa (+) group] or were left untreated [Varroa (−) group]. This established four treatment combinations within each Nosema treatment group: (1) low-MMR Varroa (−), (2) high-MMR Varroa (−), (3) low-MMR Varroa (+) and (4) high-MMR Varroa (+), each with five replicates. Overall mite mortality in high-MMR bees (0.12±0.02 mites per day) was significantly greater than in the low-MMR bees (0.06±0.02 mites per day). In the Nosema (−) groups bee mortality was greater in high-MMR bees than low-MMR bees but only when bees had a higher mite burden. Overall, high-MMR bees in the Nosema (−) group showed greater reductions in mean abundance of mites over time compared with low-MMR bees, when inoculated with additional mites. However, high-MMR bees could not reduce mite load as well as in the Nosema (−) group when fed with Nosema spores. Mean abundance of Nosema spores in live bees and dead bees of both strains of bees was significantly greater in the Nosema (+) group. Molecular analyses confirmed the presence of both Nosema species in inoculated bees but N. ceranae was more abundant than N. apis and unlike N. apis increased over the course of the experiment. Collectively, this study showed differential mite mortality rates among different genotypes of bees, however, Nosema infection restrained Varroa removal success in high-MMR bees.

Honey bees and their products: Bioindicators of environmental contamination

ABSTRACTHuman activities produce contaminants, the amounts and toxicity of which often exceed the environment's homeostatic capacity to cleanse itself. Hence, the systematic analysis and monitoring of the environment is increasingly a matter of urgency. Honey bees, thanks to their morphological features, and also bee products are regarded as good indicators of environmental pollution by toxic substances, be these heavy metals, radioactive elements, or persistent organic pollutants such as pesticides. Bees can carry back to the hive many contaminants deposited on utilitarian plants. The pesticides used in agriculture (especially in spring and summer when farming activities reach their peak) may not only be the cause of the large-scale mortality of bees, but can also get into bee products. The presence of xenobiotics in these products may impair their quality and properties, and put human health at risk. In this article available literature data and information on the morphological features of the honey bee, the utilization of the honey bee and its products as indicators of environmental pollution, and a historical outline of some of the legislation relating to beekeeping have been critically compared and discussed.

Genetic diversity within honey bee colonies affects pathogen load and relative virus levels in honey bees, Apis mellifera L

The evolution of polyandry is one of most highly debated topics in sociobiology. One hypothesis suggests genetic diversity increases resistance against the wide range of parasites and diseases affecting colonies. We investigated effects of manipulating genetic diversity on colony population size, fall Varroa population, Varroa and bee mortality rates, virus prevalence and concentration, and prevalence of Nosema apis Z. and Nosema ceranae F. Sister queens selected for resistance to Varroa were inseminated with either mixed semen from 12 drone sources (genetically diverse colonies, GDC) or single drone inseminated from 12 drone sources (genetically similar colonies, GSC), and colonies from these queens were compared to unrelated queens that were open-mated. When exposed to parasites and pathogens, open-mated colonies (OMC) and GDCs had larger worker populations before winter than GSCs. The bees of GDCs had higher Varroa mortality rates than those of GSCs in the field study. Within the instrumentally inseminated treatments, three pathogens occurred at lower prevalence (acute bee paralysis virus (ABPV) and N. ceranae) or concentrations (deformed wing virus, DWV) in GDCs than in GSCs. Both GDCs and GSCs that had been selected for resistance to Varroa had lower DWV concentration in spring when compared to unselected OMCs. Colonies inseminated by multiple drones and having greater within-colony genetic diversity showed reduced prevalence, concentrations in about a quarter of the pathogens assayed relative to genetically uniform colonies, and the reverse pattern was never observed.

The Potential of Bee-Generated Carbon Dioxide for Control of Varroa Mite (Mesostigmata: Varroidae) in Indoor Overwintering Honey bee (Hymenoptera: Apidae) Colonies.

The objective of this study was to manipulate ventilation rate to characterize interactions between stocks of honey bees (Apis mellifera L.) and ventilation setting on varroa mite (Varroa destructor Anderson and Trueman) mortality in honey bee colonies kept indoors over winter. The first experiment used colonies established from stock selected locally for wintering performance under exposure to varroa (n = 6) and unselected bees (n = 6) to assess mite and bee mortality and levels of carbon dioxide (CO2) and oxygen (O2) in the bee cluster when kept under a simulated winter condition at 5°C. The second experiment, used colonies from selected bees (n = 10) and unselected bees (n = 12) that were exposed to either standard ventilation (14.4 liter/min per hive) or restricted ventilation (0.24 liter/min per hive, in a Plexiglas ventilation chamber) during a 16-d treatment period to assess the influence of restricted air flow on winter mortality rates of varroa mites and honey bees. Experiment 2 was repeated in early, mid-, and late winter. The first experiment showed that under unrestricted ventilation with CO2 concentrations averaging <2% there was no correlation between CO2 and varroa mite mortality when colonies were placed under low temperature. CO2 was negatively correlated with O2 in the bee cluster in both experiments. When ventilation was restricted, mean CO2 level (3.82 ± 0.31%, range 0.43-8.44%) increased by 200% relative to standard ventilation (1.29 ± 0.31%; range 0.09-5.26%) within the 16-d treatment period. The overall mite mortality rates and the reduction in mean abundance of varroa mite over time was greater under restricted ventilation (37 ± 4.2%) than under standard ventilation (23 ± 4.2%) but not affected by stock of bees during the treatment period. Selected bees showed overall greater mite mortality relative to unselected bees in both experiments. Restricting ventilation increased mite mortality, but did not affect worker bee mortality relative to that for colonies under standard ventilation. Restricted ventilation did not affect the overall level of Nosema compared with the control. However, there was an interaction between stock, season, and time of the trial. Unselected stock showed an increase in Nosema over time in the late winter trial that did not occur in the selected stock. In conclusion, these findings suggested that restricted ventilation has potential to suppress varroa mite in overwintering honey bee colonies via a low-cost and environmentally friendly measure.

Pollen nutrition in honey bees (Apis mellifera): impact on adult health

Pollen is the main protein source for honey bees, and its quality and digestibility are important factors for bee health. We compared the effects of eight different mixed-pollen diets on queenless adult survival and physiology. The mixtures represented the pollen source for bees in a natural environment. They consisted of three to five familial pollen types, and the protein percentage varied from 8.4 to 18.1 %. The mixtures that contained mainly Asteraceae pollen were less consumed and enhanced bee mortality, suggesting that this pollen type offers poor nutritional quality and assimilation for the bees. All pollen diets promoted ovarian activation, but among the pollen-treated groups, the percentage of bees with activated ovaries was not related to the protein content of the diet, which suggests that ovarian activation may also depend on other nutrients. Survival was also positively correlated to the vitellogenin levels in the hemolymph. Our results showed that the amount of protein consumption and the pollen type influenced bee survival and physiology.

Effect of nutritional supplements on queen cell production in honey bee (Apis mellifera)

Honey bees are an important means of earning a living both at small and commercial levels. Maximum benefits can be obtained from strong colonies and in order to maintain strong colonies a good beekeeper requeens the colonies every second year. This requires a number of queens. The advances in beekeeping technology have made it possible to rear queens artificially or naturally. There is scope for improvement of these methods. The aim of the present study was to investigate if nutritional supplements could facilitate queen cell production in spring and autumn seasons. Becosule, thiamine, yeast and sugar solutions were fed to the honey bee colonies. The greatest number of queen cells was produced in the yeast fed colonies in spring. Bee mortality was observed in case of becosule. Perhaps the formulation contained some components which were toxic to honey bees. The effect on queen cell production by the different nutrients was in the order of Yeast &gt; Thiamine &gt; Becosule.

The effect of queen pheromone status on Varroa mite removal from honey bee colonies with different grooming ability.

The objective of this study was to assess the effects of honey bees (Apis mellifera L.) with different grooming ability and queen pheromone status on mortality rates of Varroa mites (Varroa destructor Anderson and Trueman), mite damage, and mortality rates of honey bees. Twenty-four small queenless colonies containing either stock selected for high rates of mite removal (n = 12) or unselected stock (n = 12) were maintained under constant darkness at 5 °C. Colonies were randomly assigned to be treated with one of three queen pheromone status treatments: (1) caged, mated queen, (2) a synthetic queen mandibular pheromone lure (QMP), or (3) queenless with no queen substitute. The results showed overall mite mortality rate was greater in stock selected for grooming than in unselected stock. There was a short term transitory increase in bee mortality rates in selected stock when compared to unselected stock. The presence of queen pheromone from either caged, mated queens or QMP enhanced mite removal from clusters of bees relative to queenless colonies over short periods of time and increased the variation in mite mortality over time relative to colonies without queen pheromone, but did not affect the proportion of damaged mites. The effects of source of bees on mite damage varied with time but damage to mites was not reliably related to mite mortality. In conclusion, this study showed differential mite removal of different stocks was possible under low temperature. Queen status should be considered when designing experiments using bioassays for grooming response.

Towards integrated control of varroa: 2)comparing application methods and doses of oxalic acid on the mortality of phoretic Varroa destructor mites and their honey bee hosts

In the past two decades, the parasitic mite Varroa destructor has become harder to control with synthetic acaricide chemicals due to genetic resistance. We determined the efficacy of the natural chemical oxalic acid (OA) in killing phoretic mites on adult worker bees under field conditions in southern England. We compared three OA application methods (trickling, spraying, and sublimation) at three or four (sublimation) doses, using 110 broodless colonies in early January 2013. Treatment efficacy was assessed by extracting mites from samples of c. 270 worker bees collected immediately before and 10 days after treatment. All three methods could give high varroa mortality, c. 93–95%, using 2.25 g OA per colony. However, sublimation was superior as it gave higher mortality at lower doses (.56 or 1.125 g per colony: trickling 20, 57% mortality; spraying 25, 86%; sublimation 81, 97%.). Sublimation using 2.25 g of OA also resulted in 3 and 12 times less worker bee mortality in the 10 days after application than either trickling or spraying, respectively, and lower colony mortality four months later in mid spring. Colonies treated via sublimation also had greater brood area four months later than colonies treated via trickling, spraying, or control colonies. A second trial in December 2013 treated 89 broodless colonies with 2.25 g OA via sublimation to confirm the previous results. Varroa mortality was 97.6% and 87 (98%) of the colonies survived until spring. This confirms that applying OA via sublimation in broodless honey bee colonies in winter is a highly effective way of controlling V. destructor and causes no harm to the colonies.

Potential Use of Buddleja Thyrsoides for the Control and Prevention of American Foulbrood Disease in Honey Bees

Abstract Paenibacillus larvae is the causative agent of American Foulbrood (AFB ), a severe disease that affects the larvae of the honeybees. The use of plant extracts are considered to be an alternative way of controlling the disease. In this study, the in vitro antimicrobial activity of Buddleja thyrsoides Lam. against the Paenibacillus species, including P. larvae, was evaluated. In Mueller-Hinton broth, the minimal inhibitory concentration (MI C) was assessed using the microdilution method. All Paenibacillus species were sensitive to the crude extract and the fractions of B. thyrsoides. The ethyl acetate (EA ) fraction showed a better result with MI C values of 1.68 - 3.36 mg/mL, followed by butanolic (BU) (MI C = 2.18 - 6.54 mg/mL), dichloromethane (DCM) (7.40 - 14.80 mg/mL), and crude extract (CE) (7.51 - 16.90 mg/mL). The toxic effect of the CE and fractions of B. thyrsoides against bees were also evaluated using the spraying application method with the same concentrations of MI Cs. Bee mortality was evident in treatment with DCM fractions only, while CE, EA , and BU extracts showed no toxic effects after 15 days of observation. Furthermore, phenolic acids, tannins, and flavonoids were identified and quantified by highperformance liquid chromatography (HPLC), and may be partially responsible for the antimicrobial properties observed. These results show, for the first time, that B. thyrsoides might be a natural alternative for the prevention/control of AFB .