1- Agricultural Research Education and Extension Organization
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Extended Abstract
Introduction and Objectives: Varroa mite (Varroa destructor Anderson and Trueman, 2000) is one of the most important parasites of the honey bee (Apis mellifera Linnaeus, 1758) colonies and the beekeeping industry all over the world. It causes great economic loss to the beekeeping industry and beekeepers by feeding on the fat body and hemolymph in different developmental stages of the bees and also by the transmission of pathogenic viral agents. In recent years, the application of chemical pesticides has led to the occurrence of mite resistance and contamination of hive products. Plant extracts are considered as a suitable alternative to chemical acaricides for the Varroa mite control. Therefore, the present study aimed to investigate the acaricidal and insecticidal activity of plant extract of Ferola pseudalliacea, Smyrnopsis aucheri, Satureja sahendica and Prangos ferulacea against Varroa mite and its host in the honey bee colonies in the climatic conditions of Kurdistan province from 2021 to 2023.
Material and Methods: Hangwan, Bilhar, Marzeh Sahandi and Logneh plants were collected from different regions of Kurdistan province in April and June 2021 and then identified. After separating the waste materials, the aerial parts of the studied plants were dehumidified and dried separately in the shade and at room temperature (28 degrees Celsius and relative humidity of 45%) and then using the device Shredder, their aerial organs were crushed and powdered. The extracts of studied plants in this research were extracted using a Soxhlet machine and absolute ethanol solvent. Then, the chemical compounds of the plants were identified using a gas chromatography device connected to a mass spectrometer (GC-MS). The present study was conducted in the form of a factorial experiment based on a completely random basic design with 14 treatments and 5 replications. Before conducting the bioassay experiments, the experimental colonies were homogenized in terms of queen age, population (adults and brood), and honey storage. Also, the initial infestation rate of hives with Varroa mites was evaluated for adult bees brood. In the present study, 70 Langstroth hives were used, which had a sticky white plastic sheet embedded in the bottom of each colony. The experimental colonies were treated with 15 ml of 20, 35, and 50% concentrations of the extracts of the mentioned plants at sunset when all the bees were present in the hive. Every 5 days at 10 am, the plastic sheet was removed from the bottom of all the colonies and the number of dead bees and mites on them was counted. After removing the dead bees and mites, a plastic sheet was again placed on the bottom of the colony. In the present study, the effect of acaricidal activity of different concentrations of each plant extract was calculated using the instructions of Allam et al. (2003). In the present study, the effect of the insecticidal activity of different concentrations of each plant extract on the growth rate of the population (adults and brood) was also evaluated. Finally, the data were analyzed using the GLM procedure embedded in the statistical software SAS V. 9.4 M6, and the mean comparisons were done using the least significant difference (LSD) method by this software.
Results: Generally, the results showed that different concentrations of the extracts of all tested plants showed relatively favorable acaricidal activity to control the Varroa mite in the present study. Based on the results of statistical analysis, the concentration of 50% of Hengvan and Logne plant extracts showed the greatest effect on the mortality percentage of Varroa mites in the studied bee colonies, and their difference is significant compared to other different concentrations of the studied plant extract (P < 0.01). The results of the effect of insecticidal activity of different concentrations of the studied plant extracts on bees showed that the mortality percentage of different concentrations of none of the extracts in the experimental treatments was more than nine percent. GC-MS analysis of plant extracts showed that E-1-propenyl sec-butyl disulfide, Z-1-propenyl sec-butyl disulfide, n-propenyl sec-butyl disulfide, Guaiol, and β-pinene in F. pseudalliacea and β- pinene, α- pinene and α -Fenchyl in P. ferulacea were the main chemical constituents.
Conclusion: Plant extracts, due to having more stability than plant essential oils, not having restrictions related to the use of organic acids, being safe for humans, bees and the environment, as a natural composition and a suitable alternative to chemical acaricides for Varroa mite control in honey bee colonies has been recommended in various studies. Our finding showed that the mortality percentage of different concentrations of studied plant extracts on bees was not more than nine percent in any of the experimental treatments. Therefore, the concentration of 50% of Hengvan and Logneh plant extracts can be suggested as a suitable alternative to synthetic acaricides to control the Varroa mite in honey bee colonies due to its favorable acaricidal activity on mites.
Introduction and Objectives: Varroa mite (Varroa destructor Anderson and Trueman, 2000) is one of the most important parasites of the honey bee (Apis mellifera Linnaeus, 1758) colonies and the beekeeping industry all over the world. It causes great economic loss to the beekeeping industry and beekeepers by feeding on the fat body and hemolymph in different developmental stages of the bees and also by the transmission of pathogenic viral agents. In recent years, the application of chemical pesticides has led to the occurrence of mite resistance and contamination of hive products. Plant extracts are considered as a suitable alternative to chemical acaricides for the Varroa mite control. Therefore, the present study aimed to investigate the acaricidal and insecticidal activity of plant extract of Ferola pseudalliacea, Smyrnopsis aucheri, Satureja sahendica and Prangos ferulacea against Varroa mite and its host in the honey bee colonies in the climatic conditions of Kurdistan province from 2021 to 2023.
Material and Methods: Hangwan, Bilhar, Marzeh Sahandi and Logneh plants were collected from different regions of Kurdistan province in April and June 2021 and then identified. After separating the waste materials, the aerial parts of the studied plants were dehumidified and dried separately in the shade and at room temperature (28 degrees Celsius and relative humidity of 45%) and then using the device Shredder, their aerial organs were crushed and powdered. The extracts of studied plants in this research were extracted using a Soxhlet machine and absolute ethanol solvent. Then, the chemical compounds of the plants were identified using a gas chromatography device connected to a mass spectrometer (GC-MS). The present study was conducted in the form of a factorial experiment based on a completely random basic design with 14 treatments and 5 replications. Before conducting the bioassay experiments, the experimental colonies were homogenized in terms of queen age, population (adults and brood), and honey storage. Also, the initial infestation rate of hives with Varroa mites was evaluated for adult bees brood. In the present study, 70 Langstroth hives were used, which had a sticky white plastic sheet embedded in the bottom of each colony. The experimental colonies were treated with 15 ml of 20, 35, and 50% concentrations of the extracts of the mentioned plants at sunset when all the bees were present in the hive. Every 5 days at 10 am, the plastic sheet was removed from the bottom of all the colonies and the number of dead bees and mites on them was counted. After removing the dead bees and mites, a plastic sheet was again placed on the bottom of the colony. In the present study, the effect of acaricidal activity of different concentrations of each plant extract was calculated using the instructions of Allam et al. (2003). In the present study, the effect of the insecticidal activity of different concentrations of each plant extract on the growth rate of the population (adults and brood) was also evaluated. Finally, the data were analyzed using the GLM procedure embedded in the statistical software SAS V. 9.4 M6, and the mean comparisons were done using the least significant difference (LSD) method by this software.
Results: Generally, the results showed that different concentrations of the extracts of all tested plants showed relatively favorable acaricidal activity to control the Varroa mite in the present study. Based on the results of statistical analysis, the concentration of 50% of Hengvan and Logne plant extracts showed the greatest effect on the mortality percentage of Varroa mites in the studied bee colonies, and their difference is significant compared to other different concentrations of the studied plant extract (P < 0.01). The results of the effect of insecticidal activity of different concentrations of the studied plant extracts on bees showed that the mortality percentage of different concentrations of none of the extracts in the experimental treatments was more than nine percent. GC-MS analysis of plant extracts showed that E-1-propenyl sec-butyl disulfide, Z-1-propenyl sec-butyl disulfide, n-propenyl sec-butyl disulfide, Guaiol, and β-pinene in F. pseudalliacea and β- pinene, α- pinene and α -Fenchyl in P. ferulacea were the main chemical constituents.
Conclusion: Plant extracts, due to having more stability than plant essential oils, not having restrictions related to the use of organic acids, being safe for humans, bees and the environment, as a natural composition and a suitable alternative to chemical acaricides for Varroa mite control in honey bee colonies has been recommended in various studies. Our finding showed that the mortality percentage of different concentrations of studied plant extracts on bees was not more than nine percent in any of the experimental treatments. Therefore, the concentration of 50% of Hengvan and Logneh plant extracts can be suggested as a suitable alternative to synthetic acaricides to control the Varroa mite in honey bee colonies due to its favorable acaricidal activity on mites.
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