Search Results (240)

Entomopathogenic fungi are among the most promising non-chemical alternatives for the control of many serious phytophagous insect pests, such as moth species. The present research investigates the use of the little-studied entomopathogenic fungus Beauveria varroae as a biocontrol agent against the notorious pests Helicoverpa armigera and Sesamia nonagrioides in laboratory conditions. Conidial suspensions of B. varroae were prepared at 10³-10⁴-10⁵-10⁶-10⁷-10⁸ conidia/mL to assess their insecticidal potential. In this study, we used 100 3rd-instar larvae for each concentration. During the lab bioassays, almost complete mortality of 35–96.6% was recorded for H. armigera larvae and 40–96.6% for S. nonagrioides larvae 10 days after exposure. The lethal effect of the entomopathogen was related to both dose and exposure time of the entomopathogen, with higher concentrations resulting in increased mortality. The survival effect of S. nonagrioides and H. armigera larvae was dependent on the hazard effect of the used dose and the exposure time. These findings indicate that B. varroae has potential as a biocontrol agent. Further research will elucidate this new isolate and optimize application methods in field conditions. Full article

Effective control of the parasitic mite Varroa destructor in honey bee (Apis mellifera) colonies relies on integrated pest management (IPM) strategies to prevent mite populations from reaching economic injury levels. Formulations of oxalic acid combined with glycerin may provide a viable summer treatment option in continental Northern climates. This study evaluated the efficacy of oxalic acid and glycerin strips compared to oxalic acid dribble and 65% formic acid when applied in mid-August. Mite levels and colony health parameters were assessed, and honey samples from oxalic acid-treated colonies were analyzed for residue levels. Results showed that the oxalic acid and glycerin strips had a moderate acaricidal efficacy (55.8 ± 3.2%), which was significantly higher than those of 65% formic acid (42.6 ± 3.2%) and oxalic acid dribble (39.5 ± 4.3%), which did not differ between them, suggesting potential for summer mite control. No significant adverse effects on cluster size, worker mortality, queen status, or colony survival were observed. Oxalic acid and glycerin increased the proportion of spotty brood patterns at early timepoints after treatment, but recovery was noted after 45 days of starting the treatment. Similar effects on brood were observed with 65% formic acid 14 days after starting the treatment, with recovery by 28 and 45 days after starting the treatment. No significant differences in oxalic acid residues in honey from the control and treatment colonies were found. Oxalic acid and glycerin strips might help control varroa mite populations, delaying their exponential growth and helping reduce economic losses for beekeepers, but this treatment should be considered as part of an IPM strategy and not a stand-alone method for V. destructor control. Full article

Automatic recognition systems (ARS) have been proposed in scientific and technological research for the care and preservation of endangered species; these systems, consisting of Internet of Things (IoT) devices and object-recognition techniques with artificial intelligence (AI), have emerged as proposed solutions to detect and prevent parasite attacks on Apis mellifera bees. This article presents a pilot ARS for the recognition and analysis of honeybees at the hive entrance using IoT devices and automatic object-recognition techniques, for the early detection of the Varroa mite in test apiaries. Two object-recognition techniques, namely the k-Nearest Neighbor Algorithm (kNN) and Graph Neural Network (GNN), were evaluated with an image dataset of 600 images from a single beehive. The results of the experiments show the viability of using GNN in real environments. GNN has greater accuracy in bee recognition, but with greater processing time, while the kNN classifier requires fewer processing resources but has lower recognition accuracy. Full article

Honey bees (Apis mellifera) are major pollinators, playing a critical role in global food production, biodiversity, and ecosystem stability. However, their populations are increasingly threatened by multiple interacting stressors, including pesticide exposure. Among these, agricultural insecticides and anti-Varroa acaricides such as dinotefuran and amitraz can persist in hive matrices, resulting in chronic and combined exposure. This study investigates the low lethal (LC₁₀ and LC₃₀) effects of these compounds, individually and in combination, on honey bee survival, immune function, oxidative stress responses, detoxification pathways, and hypopharyngeal gland morphology. Both pesticides negatively affected honey bee health at low lethal concentrations, with dinotefuran showing higher toxicity. Exposure led to the reduced survival, suppression of vitellogenin expression, and dysregulation of genes related to antioxidant defense, immunity, and detoxification. Additionally, high concentrations of dinotefuran and its combination with amitraz impaired hypopharyngeal gland morphology. Notably, co-exposure resulted in synergistic toxic effects, exacerbating physiological damage beyond individual treatments. These findings emphasize the potential risks of combined exposure to agricultural and beekeeping pesticides. A more comprehensive risk assessment and stricter regulations are urgently needed. Full article

Background/Objectives: The objectives of this study were to identify the genetic effects involved in the expression of individual honeybee grooming behavior in response to Varroa destructor and to determine if there is an association between the expression of this behavior and the infestation levels of Varroa in the honeybee colonies. Methods: The study was conducted in a population of 112 colonies composed of six segregating genetic groups that were derived from two honeybee lines that were selected for high and low individual honeybee grooming behavior. The individual honeybee grooming behavior of 3974 workers from the 112 colonies was measured by the time it takes a bee to respond in performing grooming behavior after a mite was placed on her body. The population growth of Varroa in the colonies was measured over a period of six months. Results: Differences between the genetic groups were found in the expression of individual honeybee grooming behavior (p < 0.01). The distribution of means of the genetic groups fits a genetic additive and dominance effects model for the expression of individual honeybee grooming behavior (r² = 0.95; p < 0.01). Differences between the genetic groups were found in the colony population growth of Varroa over a period of six months (p < 0.01). A positive correlation was found between the mean individual honeybee grooming behavior of the colonies and the Varroa level of infestation in the colonies (r = 0.57; p < 0.01). Conclusions: The results indicate that additive and dominance genetic effects are associated with honeybee individual grooming behavior and that this trait has an effect on the levels of Varroa infestation in the colonies. Full article

Νatural compounds such as lactic, acetic, formic, and oxalic acid and thymol are currently registered for use against Varroa destructor in apiaries in Europe. Complex botanical extracts are yet to be authorized, despite their beneficial ecofriendly profile and advantages in terms of resistance management. This study examined the fumigant activity of the essential oil (EO) of oregano, clove, lavender, dittany, bay laurel, sweet orange, peppermint, blue gum, and lemon balm against V. destructor in laboratory bioassays (Petri dishes). The most effective EOs were those of Origanum vulgare, Syzygium aromaticum, and Origanum dictamnus. These three EOs yielded 33.75% carvacrol, 58.64% eugenol, and 69.77% carvacrol and exhibited significant activity from 18 h of exposure to 0.0013 μL/cm until 48 h of exposure to 0.0068 μL/cm³. Origanum vulgare’s first calculated LC₅₀ value was 0.003 μL/cm³ after 24 h of mites’ exposure to EO vapors. The LC₅₀ values stabilized for oregano, clove, and dittany at 0.001, 0.002, and 0.002 μL/cm³ of 24 h exposure, respectively. This first indication of fumigant miticidal activity in Petri dishes is a promising first step before scaling up to field experiments. Full article

Varroa destructor, an ectoparasitic mite of honey bees, is a major contributor to global colony declines. To manage infestations, beekeepers frequently apply both synthetic and organic miticides—sometimes in combination. While much attention has been given to foragers’ pesticide exposure, nurse bees are also at risk due to direct miticide contact and prolonged exposure to residuals in hive matrices. Despite this, little is known about the effects of sequential miticide applications on nurse bees. In this study, we evaluated the toxicities of single and pairwise consecutive applications of three synthetic miticides (fluvalinate, coumaphos, and amitraz) and two organic miticides (formic acid and oxalic acid) at field-realistic concentrations. Miticides were topically applied to nurse bees with 24 h between consecutive treatments. Synthetic miticides caused minimal mortality, while both organic miticides—especially formic acid—significantly reduced survivorship. Consecutive treatments generally produced mortality rates comparable to that of the corresponding organic miticide alone, indicating that observed toxicities were primarily driven by the organic agents. Notably, the fluvalinate–formic acid combination induced no significant adverse effects. These findings highlight the need for caution when using miticides in combination and support the development of safer application strategies to protect vulnerable in-hive bee populations.. Full article

Varroa destructor is a parasitic mite of honeybees that is considered one of the main problems in beekeeping today. The reduction in the efficacy of conventional miticides and the presence of residues in beehives highlight the need to investigate new organic products as alternative treatments. Postbiotic products have been shown to decrease mite viability in in vitro experiments. However, their use in beehives has not yet been assessed. The aim of this study was to test the efficacy of postbiotics and oxalic acid against V. destructor under field conditions. Two experiments were performed during the summer and autumn seasons, with four study groups: control (C), postbiotic (POS), oxalic acid (OX), and both combined (POX). Phoretic and brood V. destructor were determined at the beginning and end of the study to assess their evolution, as well as the percentage effectiveness of each treatment by registering the mite fall in beehive sanitary bottoms. Postbiotic alone did not show a significant effect on V. destructor under field conditions. However, the combined treatment of postbiotics and oxalic acid improved the results obtained with oxalic acid alone, resulting in greater effectiveness and reduction of phoretic and brood V. destructor. Full article

Honeybees are vital for pollination and the overall health of ecosystems. Since the 18th century, the intricate biology of honeybees has been a subject of scientific inquiry. Understanding their biological and behavioral characteristics is essential for effective beekeeping, honey production, and ecosystem sustainability. This review examines the environmental impact and management practices on the health of local honeybees in Algeria, focusing on Apis mellifera intermissa and Apis mellifera sahariensis. We summarize research findings on genetic diversity, morphometric traits, behavioral characteristics, and adaptation of local honeybees. Additionally, we discuss the threats posed by abiotic and biotic stressors and highlight the importance of conservation and sustainable management. The reviewed studies indicate that environmental factors significantly influence the behavioral characteristics and adaptation of local honeybees. Notably, the hygienic behavior of A. m. intermissa contributes to their resistance against diseases and the Varroa destructor mite. Further research in these areas is important for enhancing our understanding of honeybee health and population dynamics in Algeria, thereby informing strategies for sustainable beekeeping practices. Full article

Beekeeping is facing a serious crisis due to climate change and diseases such as bee mites (Varroa destructor), which have led to declining populations, collapsing colonies, and reduced beekeeping productivity. Bee mites are small, reddish-brown in color, and difficult to distinguish from bees. Rapid bee mite detection techniques are essential for overcoming this crisis. This study developed a technology for recognizing bee mites and beekeeping objects in beecombs using the You Only Look Once (YOLO) object detection algorithm. The dataset was constructed by acquiring RGB images of beecombs containing mites. Regions of interest with a size of 640 × 640 pixels centered on the bee mites were extracted and labeled as seven classes: bee mites, bees, mite-infected bees, larvae, abnormal larvae, and cells. Image processing, data augmentation, and stratified data distribution methods were applied to enhance the object recognition performance. Four datasets were constructed using different augmentation and distribution strategies, including random and stratified sampling. The datasets were partitioned into training, testing, and validation sets in a 7:2:1 ratio, respectively. A YOLO-based model for the detection of bee mites and seven beekeeping-related objects was developed for each dataset. The F1 scores for the detection of bee mites and seven beekeeping-related objectives using the YOLO model based on original datasets were 94.1% and 91.9%, respectively. The model applied data augmentation, and stratified sampling achieved the highest performance, with F1 scores of 97.4% and 96.4% for the detection of bee mites and seven beekeeping-related objects, respectively. The results underscore the efficacy of using the YOLO architecture on RGB images of beecombs for simultaneously detecting bee mites and various beekeeping-related objects. This advanced mite detection method is expected to contribute significantly to the early identification of pests and disease outbreaks, offering a valuable tool for enhancing beekeeping practices. Full article

Beekeepers use a variety of methods to control Varroa destructor (varroa). Chemical control relies heavily on flumethrin, amitraz, coumaphos, and tau-fluvalinate products. However, increasing colony losses in recent years have been linked to the development of resistance in varroa mites to these insecticides. Varroa mites develop mutations in the voltage-gated sodium channel (VGSC) that confer resistance to pyrethroids such as flumethrin. Specifically, researchers have identified substitutions of the leucine amino acid at VGSC L925 with isoleucine, methionine, or valine. This study investigated phenotypic and genotypic resistance to flumethrin in varroa populations in Muğla, Türkiye. LD₅₀ values (lethal dose for 50% mortality) were quantified, and PCR and sequencing were used to analyze the VGSC L925 gene region. The PCR results confirmed mutations in the target gene region in all samples. Sequencing revealed that 95% of the population carried homozygous resistant alleles, while 5% were heterozygous. At the VGSC L925 locus, leucine was replaced by isoleucine (91%), methionine (6%), and valine (3%). Phenotypic assays showed an average LD₅₀ value of 49.1 µg (range: 31–61.8 µg). Comparison of LD₅₀ between resistant and susceptible populations was not possible because no susceptible individuals were identified. Despite the resistance, mortality increased with escalating doses, suggesting that current protocols may be temporarily mitigating infestations. However, urgent dose adjustments and alternative control strategies are critical to prevent imminent colony collapse. Full article

Honey bees (Apis mellifera) play a crucial role in global food production through the pollination of various crops. These vital insects are susceptible to a range of viral pathogens that can disrupt their normal behavior and physiology, ultimately affecting colony dynamics and survival. There are diverse viruses that infect honey bees at different life stages, with a year-round prevalence. There are multiple pathways through which viruses can be transmitted among colonies. Notably, there is also a lack of commercial treatments against viral infections in bees, but some promising strategies exist to mitigate their negative effects, including vector control, and the implementation of good beekeeping practices and biosecurity measures. While methods for treating infected colonies have garnered attention, they receive less focus compared to aspects like transmission methods and seasonal prevalence of viruses. This article aims to review the aforementioned strategies in light of the available literature. It presents succinct and practical approaches categorized based on their potential direct or indirect effects on viruses, providing beekeepers and researchers with an overview of both fully established and still-developing methods. Controlling the ectoparasitic Varroa destructor mite population, which significantly impacts viral prevalence and virulence in bees, is crucial for reducing infections. Practical approaches such as selectively breeding honey bee populations resistant to viruses and ensuring proper nutrition are important strategies. Moreover, genetic methods have also been proposed and tested. The article not only emphasizes these methods but also discusses knowledge gaps and suggests future solutions to improve the health and productivity of honey bee colonies. Full article

Infestation by Varroa destructor is responsible for high mortality rates in Apis mellifera colonies worldwide. This study was designed to develop and test under field conditions a new free software (VarroDetector) based on a deep learning approach for the automated detection and counting of Varroa mites using smartphone images of sticky boards collected in honeybee colonies. A total of 204 sheets were collected, divided into four frames using green strings, and photographed under controlled lighting conditions with different smartphone models at a minimum resolution of 48 megapixels. The Varroa detection algorithm comprises two main steps: First, the region of interest where Varroa mites must be counted is established. From there, a one-stage detector is used, namely YOLO v11 Nano. A final verification was conducted counting the number of Varroa mites present on new sticky sheets both manually through visual inspection and using the VarroDetector software and comparing these measurements with the actual number of mites present on the sheet (control). The results obtained with the VarroDetector software were highly correlated with the control (R² = 0.98 to 0.99, depending on the smartphone camera used), even when using a smartphone for which the software was not previously trained. When Varroa mite numbers were higher than 50 per sheet, the results of VarroDetector were more reliable than those obtained with visual inspection performed by trained operators, while the processing time was significantly reduced. It is concluded that the VarroDetector software Version 1.0 (v. 1.0) is a reliable and efficient tool for the automated detection and counting of Varroa mites present on sticky boards collected in honeybee colonies. Full article

Honey bees (Apis mellifera) bred for resistance to the parasitic mite, Varroa destructor, were examined for potential Varroa resistance mechanisms following bidirectional selection for low (resistant) or high (susceptible) Varroa population growth (LVG and HVG, respectively) based on mite fall in colonies at two different time points. Hygienic and grooming behavior rates in LVG colonies were significantly higher than those in HVG colonies for two out of three generations of selection, indicating that behavioral resistance to the mite increased. For the third generation, grooming start time was significantly shorter, and grooming intensity more frequent in LVG bees than in HVG bees. Cellular immunity was increased as well, based on significantly higher haemocyte concentrations in non-parasitized and Varroa-parasitized LVG bees. Humoral immunity was increased with Varroa-parasitized LVG bees, which had significantly higher expression of the antimicrobial peptide gene, hymenoptaecin 2. In addition, antiviral resistance may be involved as there were significantly lower levels of deformed wing virus (DWV) in Varroa-parasitized LVG bees. While selection for LVG and HVG bees was solely based on Varroa population growth, it appears that behavioral, cellular, and humoral mechanisms were all selected along with this resistance. Thus, LVG resistance appears to be a multi-gene trait, involving multiple resistance mechanisms. Full article

Pollen is bees’ primary source of proteins. Using pollen substitutes could reduce colony losses in areas with limited floral resources. In this study, we compared the effects of pollen substitutes made from intact proteins versus free amino acids on bee survival, as well as the levels of vitellogenin (vg), major royal jelly protein 1 (mrjp1), and deformed wing virus (DWV). Our study revealed no significant differences in vg mRNA levels between bees fed intact protein and free amino acid diets. However, mrjp1 mRNA levels were higher in bees fed free amino acid diets, suggesting that the availability of amino acids affects the expression of this nutritionally regulated gene differently. Thus, the combined expression of vg and mrjp1 could be used to assess the nutritional value of different pollen substitutes. Our results also indicate that bees fed diets rich in free amino acids exhibited high levels of DWV and increased mortality during the first week, even though they showed a high expression of genes related to good nutrition. In contrast, bees fed an intact protein diet showed the lowest DWV levels during the first two weeks, although viral infection increased afterward. These results suggest that ingested free amino acids are quickly absorbed in the intestine, transported in the hemolymph, and taken up by cells, where they can facilitate viral replication. On the other hand, ingested intact proteins may undergo slower digestion and gradual release of amino acids in the hemolymph, which may not trigger an overt DWV infection. Possible interactions among Varroa mites, DWV infection, and nutrition are also discussed. Full article