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The susceptibility of the dusky wireworm, Agriotes obscurus (L.) (Coleoptera: Elateridae), to different species and strains of entomopathogenic nematodes was tested in a virulence assay in the laboratory. Larvae were exposed to different nematode doses of 50 and 100 IJs/cm2. At a dose of 50 IJs/cm2, only a commercial strain Heterorhabditis bacteriophora Poinar and the native strain Steinernema carpocapsae (Weiser) B14 caused increased mortality compared with the control (11.1% and 13.3% mortality, respectively). At the higher dose tested, all strains (except Steinernema sp. D122) were virulent to A. obscurus larvae. Steinernema carpocapsae B14 caused higher mortality of wireworm (75.6%) and was used for the assay conducted in cages, with a dose of 100 IJs/cm2, in field conditions. The results showed that S. carpocapsae B14 controlled 48.3% of A. obscurus larvae, demonstrating that some entomopathogenic nematodes have the potential to control larvae of A. obscurus. However, further work is needed to improve their efficacy. 相似文献
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绿原酸提高舞毒蛾核型多角体病毒(LdNPV)的致病力 总被引：1，自引：0，他引：1
【目的】明确绿原酸(chlorogenic acid,CA)对舞毒蛾核型多角体病毒Lymantria dispar necleopolyhydrovirus(Ld NPV)致病力的影响,为舞毒蛾的防治提供参考依据。【方法】采用食料给毒法进行生物测定,测定舞毒蛾2龄幼虫对单独Ld NPV及添加绿原酸的Ld NPV(CA+Ld NPV)的剂量及致死时间响应。【结果】CA+Ld NPV与单独Ld NPV对舞毒蛾2龄幼虫的剂量及时间响应间有显著差异,二者对舞毒蛾2龄幼虫的致死中浓度(LC50)分别为161.8 OBs/μL(95%的置信区间为105.6~235.3 OBs/μL)和264.4 OBs/μL(95%的置信区间为178.6~384.0 OBs/μL),前者对舞毒蛾的致病力较后者强。CA+Ld NPV对舞毒蛾2龄幼虫的致死中时间(LT_(50))较Ld NPV的短,当Ld NPV浓度为590 OBs/μL,CA+Ld NPV及Ld NPV对舞毒蛾2龄幼虫的LT_(50)分别为9.9 d和12.3 d;当Ld NPV浓度为5 900 OBs/μL时,则LT_(50)分别为6.9 d和8.0 d。绿原酸降低了Ld NPV对舞毒蛾幼虫的致死中浓度,缩短了致死中时间。【结论】绿原酸可提高Ld NPV对舞毒蛾2龄幼虫的致病力,其机理有待进一步研究。 相似文献
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A. Schmitt I. L. Bisutti E. Ladurner M. Benuzzi B. Sauphanor J. Kienzle D. Zingg K. Undorf‐Spahn E. Fritsch J. Huber J. A. Jehle 《Journal of Applied Entomology》2013,137(9):641-649
Thirty‐five codling moth (CM, Cydia pomonella L., Lepidoptera, Tortricidae) populations collected in different commercial orchards in six European countries were tested for their susceptibility to Cydia pomonella granulovirus (CpGV‐M). Including previously published data on CpGV‐M resistance, a total of 38 CM colonies showed considerably elevated LC50 values, independent of the country origin. When only few test individuals are available, determination of mortality of neonate larvae at a discriminating concentration range of 104 to 106 OB/ml (>log4) as a direct measure of percentage susceptible individuals in a CM population is more advisable than calculation of LC50 values. The >log4 mortality alone or in combination with the LC50 value can be used for identification of resistance in a population. Results indicated a locally separated but widely spread occurrence of CM populations with low susceptibility to CpGV‐M. The most plausible hypothesis for the emergence of CpGV‐M resistance is its selection by repeated use of CpGV products. 相似文献
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球孢白僵菌Beauveria bassiana (Balsamo) Vuillemin是最重要的昆虫病原真菌,广泛用于防治世界各地的多种害虫.本研究评价了球孢白僵菌9个菌株对赤拟谷盗Tribolium castaneum (Herbst)成虫的致病性.将15头赤拟谷盗成虫浸入到4个浓度(1×106,l×107,l×lo8和l×109个分生孢子/mL)的白僵菌菌株中20 s,14 d内每日记录成虫的死亡率.结果表明:IRAN 440C菌株对赤拟谷盗成虫的LC50最低(5.04 ×l07个分生孢子/mL),IRAN187C菌株的最高(5.05 ×lo8个分生孢子/mL);DEBI 005菌株对赤拟谷盗成虫的LT5o最短(2.88 d),DEBI 014菌株的最长(4.96 d).根据LC50,LT50和死亡率结果得出IRAN 440C是防治这一害虫的理想菌株. 相似文献
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Molecular serotyping,virulence gene profiling and pathogenicity of Streptococcus agalactiae isolated from tilapia farms in Thailand by multiplex PCR 
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下载免费PDF全文 K. Kannika D. Pisuttharachai P. Srisapoome J. Wongtavatchai H. Kondo I. Hirono S. Unajak N. Areechon 《Journal of applied microbiology》2017,122(6):1497-1507
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J. Lordan S. Alegre G. Alins M. J. Sarasúa A. Morton F. García del Pino 《Journal of Applied Entomology》2014,138(9):635-643
Use of predators, parasitoids and entomopathogens as biocontrol agents in pome fruit production can lead to more efficient and sustainable pest management programmes. The European earwig (Forficula auricularia Linnaeus [Dermaptera: Forficulidae]) is a major predator of key pests in pome fruit orchards, and entomopathogenic nematodes (EPNs) of the families Steinernematidae and Heterorhabditidae are obligate parasites of a large number of insect species. Therefore, the interaction between earwigs and EPNs can play an important role in pest management programmes. Susceptibility of the European earwig to Steinernema carpocapsae, Steinernema feltiae (Steinernematidae) and Heterorhabditis bacteriophora (Heterorhabditidae) was evaluated. S. carpocapsae was the only tested EPN capable of killing the European earwig. However, the European earwig can detect the presence of S. carpocapsae and therefore avoid nematode‐treated shelters. An earwig deterrent activity in EPN‐killed codling moth larvae that reduces the foraging of European earwig on insect cadavers containing nematodes and allows nematodes to complete their life cycle was also assessed with the three species of nematodes. These findings suggest a positive compatibility between the European earwig and EPNs. 相似文献
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I. Natividad‐Bonifacio F.J. Fernández E.I. Quiñones‐Ramírez E. Curiel‐Quesada C. Vázquez‐Salinas 《Journal of applied microbiology》2013,114(5):1539-1546
Aims
This work aims to demonstrate the presence of several genes and factors associated with virulence in strains isolated from the environment at Pueblo Viejo Lagoon, State of Veracruz, Mexico.Methods and Results
In this study, we investigated the production of V. vulnificus virulence factors, as cytolysin (haemolysin), RTX toxin, metalloprotease, siderophores, capsular polysaccharide, adhesion structures (like type IV pili), and polar and lateral flagella, involved in swimming and swarming (or, at least, the presence of genes encoding some of them) in 40 strains of V. vulnificus isolated from water and food. The results indicate that strains of environmental origin possess potential virulence characteristics.Conclusions
Caution should be exercised when consuming raw shellfish (especially by those more susceptible risk groups).Significance and Impact of the Study
This is the first work focused on the evaluation of V. vulnificus virulence factors in Mexico. 相似文献8.
Virulence markers associated with Trueperella pyogenes infections in livestock and companion animals 下载免费PDF全文
下载免费PDF全文 R.M. Risseti E. Zastempowska M. Twarużek H. Lassa J.C.F. Pantoja A.P.C. de Vargas S.T. Guerra C.A.D. Bolaños C.L. de Paula A.C. Alves B.S. Colhado F.V.R. Portilho C. Tasca G.H.B. Lara M.G. Ribeiro 《Letters in applied microbiology》2017,65(2):125-132
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Median lethal concentrations (LC₅₀) were determined for four nematode populations (two strains of Steinernema feltiae, a S. feltiae hybrid, and S. bibionis) against fifth-instar fall armyworm (Spodoptera frugiperda) larvae and for the most virulent of these nematodes against different instars and stages of the insect. Based on lack of overlap of 95% fiducial limits, there were significant differences in virulence among the four nematodes. The LC₅₀ ranged from 7.6 to 33.3 nematodes/ 0.7 ml water, and slopes of the log dose-probit regression lines were similar except for the S. feltiae All strain. First-instar fall armyworms suffered virtually 100% mortality from the S. feltiae Mexican strain at 1.0 nematode/0.7 ml, and LC₅₀ were 2.3 and 7.9 nematodes/0.7 ml in third-instar and fifth-instar larvae, respectively. Pupae had 7-20% mortality at doses ranging from 30 to 60 nematodes/0.7 ml. 相似文献
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GuoQing Li FeiFei Liu JieQiong Li QianLi Liu ShuaiFei Chen 《Journal of Phytopathology》2016,164(5):348-353
China is the largest walnut producer in the world, and walnut trees, especially English walnut, are widely distributed in the country. Species of Botryosphaeriaceae include important plant pathogens that can cause diseases on many tree crops including English walnut. Recently, disease symptoms caused by Botryosphaeriaceae were observed on English walnut branches or kernels from Beijing, Henan and Sichuan provinces in China. Based on morphological characteristics and phylogenetic analyses of the ITS rDNA sequences and translation elongation factor 1‐alpha (TEF‐1α) gene regions, Botryosphaeria dothidea and Lasiodiplodia pseudotheobromae were identified. Pathogenicity tests showed that both species are virulent to English walnut. To our knowledge, this is the first report of L. pseudotheobromae infecting English walnut in the world. 相似文献
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D. M. Ma L. Q. Han J. J. Bai S. J. Li J. J. Fan L. Y. Yu Y. C. Quan 《Animal genetics》2014,45(3):421-426
Growth hormone releasing hormone (GHRH) regulates the secretion of growth hormone (GH) in the pituitary gland. A 66‐bp deletion (c.‐923_‐858del) was detected in the 5′‐flanking sequence of the largemouth bass (Micropterus salmoides) GHRH gene. In two cultured random populations of adult individuals (A: n = 170 and B: n = 150), the genotype ratios of +/+:+/? were 2.5:1 and 2.8:1 respectively. Only one ?/? fish was detected. A Largemouth bass family was constructed with two heterozygous individuals (+/?) as parents. The genotype ratio of +/+:+/?:?/? in the filial generation embryos was 1:1.6:0.1 at the neurula and 1:2:0 at hatched larvae stages. This indicated that the 66‐bp deletion was a recessive lethal site and that homozygous individuals (?/?) died off in embryonic development. The growth traits (body weight, body length and body depth) were measured, and the GHRH mRNA expression levels in brain tissue were detected using real‐time PCR. The effects of genotype (+/?) on growth traits and GHRH mRNA expression were not significant. Although the cause of death was not clear, the results hint that the 66‐bp deletion site in GHRH 5′‐flanking sequence significantly affects the livability in largemouth bass embryonic development. 相似文献
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Alfredo Seiiti Urashima Augusto Freitas Alves Flávio Nunes Silva Danielle Oliveira Rodrigo Gazaffi 《Journal of Phytopathology》2017,165(7-8):414-424
Brazil is blast disease hot spot because severe epidemics have occurred among wheat, triticale, rye, barley and oat crops. Although the first outbreak of barley blast appeared in 1998, little information is available. Therefore, this study aimed to examine host range, mating type composition and population structure of Magnaporthe sp. from a single barley field in São Paulo, Brazil. To examine pathogenicity, 25 Magnaporthe isolates were inoculated on five, three, two and two cultivars of barley, wheat, oat and rice, respectively, and one cultivar each of rye, corn, sorghum, triticale and certain weeds (Cenchrus echinatus, Setaria geniculata, Brachiaria plantaginea and Eleusine indica). Mating type distribution of 33 isolates was investigated by molecular tools. The genotypic divergence of 41 barley and five wheat isolates was investigated by 15 random amplified polymorphic DNA primers and unweighted pair group method with arithmetic mean. The host range of the barley blast pathogen included wheat, oat, rye and triticale but not rice and weeds. Sexual reproduction appeared to not be involved in the high genotypic diversity because only a single isolate, MAT1‐2, was identified. The majority of barley isolates clustered together with wheat blast, except for four, suggesting a different origin. 相似文献
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The invasive multicoloured Asian lady beetle, Harmonia axyridis (Pallas), and the indigenous twelve spotted lady beetle, Coleomegilla maculata DeGeer (Col., Coccinellidae), are two important generalist predators commonly found in apple orchards in Quebec, Canada. Both species are exposed to two reduced‐risk insecticides, recently adopted to control codling moth, Cydia pomonella (L.) (Lep., Tortricidae) in south‐eastern Canada. Chlorantraniliprole (Altacor® 35 WG), an anthranilic diamide insecticide, causes paralyses of the muscle cells by interfering with the insect ryanodine receptors, whereas novaluron (Rimon® EC 10), a benzoylphenyl urea, inhibits the chitin synthesis. The aim of this study was to compare the sensitivity of both the invasive ladybeetle H. axyridis and the indigenous C. maculata to reduced‐risk insecticides through the assessment of lethal effect on eggs and larvae following topical contact, ingestion of treated prey and exposure to fresh residues, at field rates (50.75 g a.i./ha chlorantraniliprole and 100 g a.i./ha novaluron) in laboratory conditions. Eggs of both species were not affected. Following 6 days of residual contact, chlorantraniliprole and novaluron caused more than 98% mortality to larvae of both ladybeetle species. In topical contact and ingestion trials, chlorantraniliprole caused less than 18% mortality to larvae of the two species after 6 days following exposure. Novaluron had a drastically different impact on the two predators. It did not affect the indigenous C. maculata, whereas it killed 91% and 96% of H. axyridis individuals after 6 days, respectively, following topical contact and ingestion. These results illustrate a differential sensitivity to novaluron between two relatively close species (subfamily Coccinellinae), a potential impact on the invasion process by H. axyridis, and consequently on the ladybeetle assemblage in the field. 相似文献
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Distribution of virulence genes and multiple drug‐resistant patterns amongst different phylogenetic groups of uropathogenic Escherichia coli isolated from patients with urinary tract infection 下载免费PDF全文
下载免费PDF全文 A. Derakhshandeh R. Firouzi M. Motamedifar A. Motamedi Boroojeni M. Bahadori S. Arabshahi A. Novinrooz S. Heidari 《Letters in applied microbiology》2015,60(2):148-154