scholarly journals A gene drive does not spread easily in populations of the honey bee parasite Varroa destructor

2021 ◽  
Author(s):  
Nicky R. Faber ◽  
Adriaan B. Meiborg ◽  
Gus R. McFarlane ◽  
Gregor Gorjanc ◽  
Brock A. Harpur
Keyword(s):  
Varroa Destructor ◽  
Management Practices ◽  
Treatment Options ◽  
Gene Drive ◽  
Colony Losses ◽  
Chemical Treatments ◽  
Varroa Mites ◽  
Neutral Gene ◽  
Physical And Chemical ◽  
Drive Time

Varroa mites (Varroa destructor) are the most significant threat to beekeeping worldwide. They are directly or indirectly responsible for millions of colony losses each year. Beekeepers are somewhat able to control Varroa populations through the use of physical and chemical treatments. However, these methods range in effectiveness, can harm honey bees, can be physically demanding on the beekeeper, and do not always provide complete protection from Varroa. More importantly, in some populations Varroa mites have developed resistance to available acaricides. Overcoming the Varroa mite problem will require novel and targeted treatment options. Here, we explore the potential of gene drive technology to control Varroa. We show that spreading a neutral gene drive in Varroa is possible but requires specific colony-level management practices to overcome the challenges of both inbreeding and haplodiploidy. Furthermore, continued treatment with acaricides is necessary to give a gene drive time to fix in the Varroa population. Unfortunately, a gene drive that impacts female or male fertility does not spread in Varroa. Therefore, we suggest that the most promising way forward is to use a gene drive which carries a toxin precursor or removes acaricide resistance alleles.

scholarly journals Evaluating toxicity of Varroa mite (Varroa destructor)-active dsRNA to monarch butterfly (Danaus plexippus) larvae

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0251884
Author(s):  
Niranjana Krishnan ◽  
Maura J. Hall ◽  
Richard L. Hellmich ◽  
Joel R. Coats ◽  
Steven P. Bradbury
Keyword(s):  
Honey Bee ◽  
Base Pair ◽  
Varroa Destructor ◽  
Sublethal Effects ◽  
Larval Mortality ◽  
Danaus Plexippus ◽  
Monarch Butterfly ◽  
Varroa Mite ◽  
Colony Losses ◽  
Varroa Mites

Varroa mites (Varroa destructor) are parasitic mites that, combined with other factors, are contributing to high levels of honey bee (Apis mellifera) colony losses. A Varroa-active dsRNA was recently developed to control Varroa mites within honey bee brood cells. This dsRNA has 372 base pairs that are homologous to a sequence region within the Varroa mite calmodulin gene (cam). The Varroa-active dsRNA also shares a 21-base pair match with monarch butterfly (Danaus plexippus) calmodulin mRNA, raising the possibility of non-target effects if there is environmental exposure. We chronically exposed the entire monarch larval stage to common (Asclepias syriaca) and tropical (Asclepias curassavica) milkweed leaves treated with concentrations of Varroa-active dsRNA that are one- and ten-fold higher than those used to treat honey bee hives. This corresponded to concentrations of 0.025–0.041 and 0.211–0.282 mg/g leaf, respectively. Potassium arsenate and a previously designed monarch-active dsRNA with a 100% base pair match to the monarch v-ATPase A mRNA (leaf concentration was 0.020–0.034 mg/g) were used as positive controls. The Varroa mite and monarch-active dsRNA’s did not cause significant differences in larval mortality, larval or pupal development, pupal weights, or adult eclosion rates when compared to negative controls. Irrespective of control or dsRNA treatment, larvae that consumed approximately 7500 to 10,500-mg milkweed leaf within 10 to 12 days had the highest pupal weights. The lack of mortality and sublethal effects following dietary exposure to dsRNA with 21-base pair and 100% base pair match to mRNAs that correspond to regulatory genes suggest monarch mRNA may be refractory to silencing by dsRNA or monarch dsRNase may degrade dsRNA to a concentration that is insufficient to silence mRNA signaling.

Effects of physical and chemical treatments upon biophysical properties and micro-relief of human skin

2008 ◽  
Vol 300 (5) ◽  
pp. 243-251 ◽  
Author(s):  
Nicolas Atrux-Tallau ◽  
Ngoc T. T. Huynh ◽  
Laurie Gardette ◽  
Cyril Pailler-Mattéi ◽  
Hassan Zahouani ◽  
...  
Keyword(s):  
Human Skin ◽  
Biophysical Properties ◽  
Chemical Treatments ◽  
Physical And Chemical

scholarly journals Puparia Cleaning Techniques for Forensic and Archaeo-Funerary Studies

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 104
Author(s):  
Jennifer Pradelli ◽  
Fabiola Tuccia ◽  
Giorgia Giordani ◽  
Stefano Vanin
Keyword(s):  
Sodium Hydroxide ◽  
Molecular Identification ◽  
Sodium Hydroxide Solution ◽  
Species Level ◽  
Post Mortem ◽  
Molecular Analyses ◽  
Chemical Treatments ◽  
Wrong Identification ◽  
Physical And Chemical

Diptera puparia may represent both in forensic and archaeo-funerary contexts the majority of the entomological evidence useful to reconstruct the peri and post-mortem events. Puparia identification is quite difficult due to the lack of identification keys and descriptions. In addition, external substances accumulated during the puparia permanence in the environment make the visualization of the few diagnostic characters difficult, resulting in a wrong identification. Six different techniques based on physical and chemical treatments have been tested for the removal of external substances from puparia to make identification at species level feasible. Furthermore, the effects of these methods on successful molecular analyses have also been tested as molecular identification is becoming an important tool to complement morphological identifications. The results of this study indicate that cleaning via warm water/soap, the sonication and treatment with a sodium hydroxide solution are the best methods to achieve a good quality of the samples.

scholarly journals Evaluating the Efficacy of 30 Different Essential Oils against Varroa destructor and Honey Bee Workers (Apis mellifera)

Insects ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1045
Author(s):  
Marian Hýbl ◽  
Andrea Bohatá ◽  
Iva Rádsetoulalová ◽  
Marek Kopecký ◽  
Irena Hoštičková ◽  
...  
Keyword(s):  
Essential Oils ◽  
Honey Bees ◽  
Varroa Destructor ◽  
Mortality Rates ◽  
Selectivity Ratio ◽  
Varroa Mites ◽  
Main Components ◽  
Honey Bee Workers ◽  
Over Time ◽  
Better Than

Essential oils and their components are generally known for their acaricidal effects and are used as an alternative to control the population of the Varroa destructor instead of synthetic acaricides. However, for many essential oils, the exact acaricidal effect against Varroa mites, as well as the effect against honey bees, is not known. In this study, 30 different essential oils were screened by using a glass-vial residual bioassay. Essential oils showing varroacidal efficacy > 70% were tested by the complete exposure assay. A total of five bees and five mites were placed in the Petri dishes in five replications for each concentration of essential oil. Mite and bee mortality rates were assessed after 4, 24, 48, and 72 h. The LC50 values and selectivity ratio (SR) were calculated. For essential oils with the best selectivity ratio, their main components were detected and quantified by GC-MS/MS. The results suggest that the most suitable oils are peppermint and manuka (SR > 9), followed by oregano, litsea (SR > 5), carrot, and cinnamon (SR > 4). Additionally, these oils showed a trend of the increased value of selective ratio over time. All these oils seem to be better than thymol (SR < 3.2), which is commonly used in beekeeping practice. However, the possible use of these essential oils has yet to be verified in beekeeping practice.

scholarly journals ИССЛЕДОВАНИЕ ВЛИЯНИЯ ОБРАБОТКИ ГОРЯЧИМ ТУМАНОМ БИОЛОГИЧЕСКИХ ПРЕПАРАТОВ И ГУМИНОВЫХ ПРОДУКТОВ СЕМЯН ЯЧМЕНЯ

2019 ◽  
Author(s):  
M.Yu. KOSTENKO ◽  
G. RYMBALOVICH ◽  
I.N. GORYACHKINA ◽  
R.V. BEZNOSYUK ◽  
G.A. BORISOV
Keyword(s):  
Mass Fraction ◽  
Treatment Options ◽  
Experimental Studies ◽  
Metabolic Energy ◽  
Potassium Humate ◽  
Protein Mass ◽  
Biological Yield ◽  
Small Grains ◽  
Humic Products ◽  
Physical And Chemical

Целью исследований явилась оценкавлияния обработки горячим туманом биологического препарата Азотовит и гуминовых продуктовГумат калия, Экоростсемян ячменя перед посевом, а также сравнение результатов с общепринятымитехнологиями обработки с помощью протравителя семян этими же препаратами. Для полноты исследований обработку производили и химическим препаратом Атик. Высокодисперсный аэрозоль получали с помощью генератора горячего тумана GreenFogBF-130.Обработку производилис помощью устройства с наклонными полками, по которым зерно многократно пересыпалось под действием силы тяжести и подвергалось перемешиванию и воздействию горячего тумана. В результате разницы температур холодного семенного материала и горячего тумана происходил фазовый переход тумана в жидкость, что позволяло получить тонкую плёнку на обрабатываемой поверхности семянячменя.Это способствовало обеззараживанию и активизации физико-химических процессов в зерне. Экспериментальные исследования включали восемь вариантов обработки и один без обработки (контроль). Оценивались результаты продуктивности и структура урожая: число растений на 1 м2, число сорных растений на 1 м2, число продуктивных стеблей (колосьев) на 1 м2, кустистость на 1 м2, продуктивная кустистость на 1 м2,среднее число зерен в колосе, масса 1000 зерен, высота стеблей, биологическая урожайность. В соответствии с ГОСТ 53900-2010 Ячмень кормовой, ГОСТ 5060-86 Ячмень пивоваренный, ГОСТ 28672-90 Ячмень.Требования при заготовках и поставках,ТРТС 021/2011 О безопасности пищевой продукции из качественных показателей рассматривались массовая доля влаги, массовая доля протеина, массовая доля клетчатки, массовая доля сахара, массовая доля жира, массовая доля золы, массовая доля крахмала, обменная энергия, крупность, мелкие зерна, сорная и зерновая примесь, фузариозные зерна, общая токсичность, микотоксиндезоксиниваленол (DON). Лучшие показатели были получены в результате аэрозольной обработки гуминовыми продуктами Гумат калия и Экорост.The aim of the research was to assess the effect of hot mist treatment of the biological preparation Azotovit and humic products potassium HUMATE, barley seeds Ecorost before sowing, as well as to compare the results with conventional technologies of treatment with the help of seed protectant with the same drugs. To complete the research and produce treatment chemicals of Atik. The highly dispersed aerosol was obtained using The greenfogbf-130 hot mist generator. The treatment was carried out using a device with inclined shelves, on which the grain was repeatedly poured under the influence of gravity and was subjected to mixing and the influence of hot fog. As a result of the temperature difference between the cold and hot mist of the seed material, a phase transition of the mist into a liquid occurred, which allowed to obtain a thin film on the treated surface of the barley seeds. This contributed to the disinfection and activation of physical and chemical processes in the grain. Experimental studies included eight treatment options and one without treatment (control). The results of productivity and crop structure were evaluated: the number of plants per 1 m2, the number of weeds per 1 m2, the number of productive stems (ears) per 1 m2, bushiness per 1 m2, productive bushiness per 1 m2, the average number of grains per ear, the weight of 1000 grains, the height of stems, biological yield. In accordance with GOST 53900-2010 barley fodder, barley brewing GOST 5060-86, GOST 28672-90 Barley. Requirements for procurement and supply, TR CU 021/2011 on food safety from qualitative indicators considered the mass fraction of moisture, mass fraction of protein, mass fraction of fiber, mass fraction of sugar, mass fraction of fat, mass fraction of ash, mass fraction of starch, metabolic energy, size, small grains, weed and grain admixture, Fusarium grains, total toxicity, mycotoxindeoxynivalenol (don). The best results were obtained as a result of aerosol treatment with humic products potassium HUMATE and Ecorost.

scholarly journals Effects of Bacterial Cell-Free Supernatant on Nutritional Parameters of Apis Mellifera and Their Toxicity Against Varroa Destructor

2020 ◽  
Vol 64 (1) ◽  
pp. 55-66
Author(s):  
Fiorella G. De Piano ◽  
Matias D. Maggi ◽  
Facundo R. Meroi Arceitto ◽  
Marcela C. Audisio ◽  
Martín Eguaras ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Varroa Destructor ◽  
High Concentration ◽  
Colony Losses ◽  
Nutritional Parameters ◽  
Low Concentrations ◽  
Bee Health ◽  
Contact Exposure ◽  
Fat Bodies ◽  
The Relationship

AbstractApis mellifera L. is an essential pollinator that is currently being affected by several stressors that disturb their ecological function and produce colony losses. Colonies are being seriously affected by the ectoparasitic mite Varroa destructor. The relationship between stressors and bee symbionts is being studied in order to enhance bee health. The goal of this study was to evaluate the effect of cell-free supernatants (CFSs) produced by Lactobacillus johnsonii AJ5, Enterococcus faecium SM21 and Bacillus subtilis subsp. subtilis Mori2 on A. mellifera nutritional parameters and their toxicity against V. destructor. Toxicity and survival bioassays were conducted on adult bees with different concentrations of CFSs. Nutritional parameters such as soluble proteins and fat bodies in abdomens were measured. Varroa destructor toxicity was analyzed by a contact exposure method and via bee hemolymph. At low concentrations, two of CFSs tends to enhance bee survival. Remarkably fat bodies maintained their levels with all CFS concentrations in the abdomens, and soluble protein increased at a high concentration of two CFSs. Toxicity against V. destructor was observed only via hemolymph, and results were in agreement with the treatment that produced an increase in bee proteins. Finally, CFS produced by L. johnsonii AJ5 could be a promising natural alternative for strengthening bee health.

scholarly journals Studies on Integrated Nutrient Management of Cowpea (Vigna unguiculata l.): A Review

2021 ◽  
pp. 148-154
Author(s):  
Bimesh Dahal
Keyword(s):  
Crop Production ◽  
Management Practices ◽  
Nutrient Management ◽  
Chemical Properties ◽  
Farming Systems ◽  
Integrated Nutrient Management ◽  
Yield Attributes ◽  
The Status ◽  
Physical Attributes ◽  
Physical And Chemical

There are many management methods for nutrient which can be specifically applied in farming systems. Integrated nutrient management (INM) generally denotes the combined use of organic and chemical fertilizers for producing crops in a sustainable manner and to maintain soil fertility as well as to supply nutrient in appropriate amount which consider social, ecological and economic impacts. This paper shows the importance and need of INM in agriculture production. Also, the relation of INM and yield attributes are analyzed and evaluated including growth and physical attributes of cowpea. The status of nutrient uptake by plant is also described along with other physical and chemical properties of soil. Finally, this paper also describes about the biofertilizer and its relation, impact and effect on crop production which can be used as a improved technology with the combination of other nutrient management practices.

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