Investigation of resistance against to flumethrin using against Varroa destructor in Türkiye.

The honeybee ectoparasite Varroa destructor is a major threat to apiculture when evaluating bee diseases and pests. While attempting to control this mite, beekeepers often depend on a small selection of authorized synthetic acaricides, such as flumethrin, which is widely used in Türkiye and globally. However, resistance to flumethrin develops due to incorrect and excessive use. In this study conducted at Ordu Beekeeping Research Institute, trial group were established including an untreated control group and group where flumethrin-based pesticides were applied. Dead varroas collected from pollen traps and live varroas collected from bees were obtained from these trial groups for molecular analysis as positive-negative controls. Varroa samples were collected from provinces representing different regions with intensive beekeeping activities such as Adana, Ankara, Bingöl, Mugla, Ordu, Sanliurfa, Tekirdag. Molecular methods were employed to investigate the resistance gene region for pyrethroids (specifically flumethrin) against V. destructor. In our study, individual DNA extractions were performed on dead parasites from colonies subjected to pyrethroid application (resistance negative control) and live parasites (resistance positive control). The DNA samples obtained were used in PCR reactions targeting the region encoding the 925th amino acid of the voltage-gated sodium channel (VGSC) gene, which is responsible for resistance formation. The DNA samples were subjected to gel electrophoresis to observe the amplification products of the expected target region. To examine the nucleotide sequence changes that encode leucine at the 925th amino acid, which is associated with resistance, DNA sequence analysis was applied to the amplification products. Out of 332 V. destructor parasites obtained from different provinces, 279 were analysed using molecular methods. It was observed that 31% of the samples showed sensitivity to flumethrin while 69% exhibited resistance to it. Among the resistant samples: 27% had homozygous isoleucine mutation; 28% had homozygous valine mutation; 2.8% had heterozygous isoleucine mutation; 8.5% had heterozygous valine mutation; and 2.8% had heterozygous methionine mutation, all of which were associated with flumethrin resistance. As a result, the rate of flumethrin resistance in parasites varied between 51% and 94% among different provinces.

PCR-Based Screening of Pathogens in Bombus terrestris Populations of Turkey.

PURPOSE: Bumblebees are an important group of insects in the pollination of various vegetables, fruits, oilseeds, legumes, and the fodder crops. Compared to honeybees, they have a wider choice of hosts and a longer flight period. These bees are used especially for the pollination of plants in greenhouses and are commercially produced for this purpose. Recently, serious decreases have been occurring in bumblebee populations due to various reasons such as pathogens, and some of species are even threatened with extinction. Due to the worldwide decline in pollinator insects, determining the distribution and prevalence of bumblebee pathogens is of great importance. Therefore, this study was conducted to determine the incidence and prevalence of pathogens in Turkish bumblebee populations and how much of each pathogen was in bumblebee samples. METHODS: A total of 172 Bombus terrestris (Linnaeus,1758) samples (21 samples from commercial enterprises, 79 samples from greenhouses and 72 samples from nature) were randomly collected from 3 provinces (Antalya, Mersin and Izmir) where greenhouse cultivation is intensively carried out in Turkey. Eighty-nine of these samples were collected in the spring and eighty-three in the autumn. The presence of four pathogens (Nosema bombi, Crithidia bombi, Apicystis bombi, and Locustacarus buchneri) was investigated by PCR using universal primers. RESULTS: The overall prevalence of Nosema bombi, Crithidia bombi, Apicystis bombi, and Locustacarus buchneri was determined as 7.55%, 9.3%, 11.62%, and 4.65%, respectively. Co-infections (5.81%) were only detected in wild-caught (nature) samples. C. bombi and A. bombi infections were detected at higher rates in the spring samples than in the autumn samples (p < 0.05). There was no significant difference between the spring and autumn samples with respect to the presence of N. bombi and L. buchneri (p > 0.05). CONCLUSION: The results obtained could be important in determining the prevalence and spread rates of the bumblebee diseases in Turkey and to determine appropriate protection measures. The information gathered should increase our knowledge about the presence of these pathogens in Turkey and could contribute to improve apiarist's practice. More studies are needed to determine the transmission pathways of these pathogens between the populations. Also, complex pathogen interactions in bumblebee populations should be considered in the future to improve bumblebee health.