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1.
AIMS: This study was to illustrate the relationship between the thermotolerance and the contents of hydrophobin-like or formic-acid-extractable (FAE) proteins in aerial conidia of Beauveria bassiana and Paecilomyces fumosoroseus produced on rice-based substrate. METHODS AND RESULTS: Survival indices of 11 isolates were separately assessed as a ratio of the viability of conidia after 3-150 min thermal stress at 48 degrees C over that of unstressed conidia and fitted well to a survival model (r(2) >/= 0.97). For a given isolate, the fitted model generated an LT(50), the time for 50% viability loss under the stress. The LT(50)s of six B. bassiana isolates (10.1-61.9 min) and five P. fumosoroseus isolates (2.8-6.2 min) were correlated (r(2) = 0.81) with FAE protein contents (6.9-23.4 microg mg(-1)). The survival indices of a fixed B. bassiana isolate after 45-min thermal stress at 48 degrees C were also correlated to the FAE protein contents from conidia produced on glucose-, sucrose-, or starch-based substrate (0.79 相似文献   

2.
The pathogenicity of 4 species of entomopathogenic fungi (Hyphomycetes species: Beauveria bassiana, Metarhizium anisopliae, Metarhizium flavoviride, and Paecilomyces fumosoroseus) to various developmental stages of Rhipicephalus sanguineus (Acari: Ixodidae) ticks was compared under laboratory conditions. The most virulent isolate, M. anisopliae-108, caused 92-96% mortality to unfed larvae and nymphs on day 7 postinfection (PI) and 100% mortality to unfed adults and engorged females on day 21 PI. The pathogenicity of M. anisopliae-108 to engorged larvae and nymphs was lower--82.6 and 60%, respectively. All tested B. bassiana, M. flavoviride, and P. fumosoroseus isolates were significantly less virulent (P < 0.05) or avirulent toward most life stages of R. sanguineus. The M. anisopliae and M. flavoviride isolates also prevented or reduced the ability of the ticks to lay eggs several days before their deaths. Female ticks infected by the fungi achieved only 11.3-60.8% of their egg-laying capacity compared with the controls.  相似文献   

3.
Strains from Paecilomyces fumosoroseus, Lecanicillium muscarium, Metarhizium anisopliae and Beauveria bassiana were examined in standardized Biotest to control the horse-chestnut leaf miner (Cameraria ohridella) in her pupal stage in winter. The fungi were pathogenic against the hibernating pupae of Cameraria ohridella at dose of 1.9 x 10(7) conidia/ml. They were aggressive, led to infection, death and mouldiness of naked pupae. Even at low temperature of 5 degrees C and 12 degrees C. L. muscarium strain V24 showed the highest pathogenicity after 4 weeks against this host, close followed by P. fumosoroseus strain P6. M. anisopliae strain 72 and 8. bassiana strain B412 were also pathogen but after a long-time period. Experiments gave information for general susceptibility of naked pupae of C. ohridella under low temperatures against entomopathogenic fungi. In further examinations it has to be tested, whether fungi can infected, when the pupae stay in their natural surroundings, the pupal cell in the leaf.  相似文献   

4.
We used a newly developed bioassay method to demonstrate for the first time the potential of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae to be used for the control of neonate larvae of Capnodis tenebrionis, a major threat to stone-fruit orchards in several countries. Four B. bassiana and four M. anisopliae isolates were all pathogenic for neonate larvae of C. tenebrionis; mortality rates 10 days after inoculation by dipping in a suspension with 10(8)conidia/ml varied from 23.5% to 100%. Three of the four M. anisopliae isolates caused 100% mortality. In most cases, postmortem hyphal growth and sporulation of M. anisopliae or B. bassiana was observed covering the larvae in their galleries. The eight isolates were also evaluated for pathogenicity to C. tenebrionis eggs at the same dosage. Only two B. bassiana isolates caused significant egg hatching reduction of 84.5% and 94.5%. Our results indicate that M. anisopliae and B. bassiana may be considered as promising for a new approach to prevent larval infestations by C. tenebrionis.  相似文献   

5.
The Brucella ovis dnaK gene, homolog to the eukaryotic hsp70 genes, was cloned by using a Drosophila melanogaster probe. Comparison of B. ovis and Escherichia coli sequences revealed a similar organization for the dnaK and dnaJ genes and putative regulatory signals. In E. coli transfected with the cloned fragment, B. ovis hsp70 was expressed at 30 and 50 degrees C apparently under the control of its own promoter. The recombinant protein and a B. ovis native protein displaying the same molecular weight were both recognized by anti-E. coli DnaK serum. Native B. ovis protein was also recognized by sera of sheep either infected or vaccinated with an attenuated Brucella strain, suggesting that Brucella hsp70 could be up-regulated during host colonization. A thermosensitive E. coli dnaK mutant transfected with the cloned fragment recovered colony-forming ability at 42 degrees C, showing that the B. ovis DnaK protein could behave as a functional heat shock protein in E. coli.  相似文献   

6.
常用化学杀螨剂对两种生防真菌孢子的相容性测定   总被引:6,自引:0,他引:6  
姜渝  冯明光 《应用生态学报》2006,17(7):1264-1268
用营养液萌发法和平板萌发法测定了10种常用化学杀螨剂与球孢白僵菌(Beauveria bassiana)和玫烟色拟青霉(Paecilomyces fumosoroseus)分生孢子的生物相容性.结果表明,营养液萌发法比平板法灵敏.以24 h内的孢子萌发率作为指标,供试杀螨剂的常用浓度及其5和10倍稀释液对活孢率的影响在不同杀螨剂间差异极显著,并在两种真菌间也存在差异.三唑锡、浏阳霉素、三氯杀螨醇和阿维菌素对生防真菌孢子的抑制力很强,不宜混用.速螨酮、克螨特、乐斯本、尼索朗及双甲脒等杀螨剂与真菌孢子的相容性优良,可与菌剂田间混用.将速螨酮、克螨特和乐斯本分别按3种浓度与白僵菌的孢子悬乳剂混配后在4 ℃恒温和室内变温下长期共贮,结果显示,3种杀螨剂对孢子活力的影响迥异,混配制剂在室内变温下的贮存期均未达到12个月,离商品化的要求差距较大.乐斯本的长期相容性相对较优,与菌剂低浓度混配可在常温下贮存6.5个月,中浓度和低浓度混配在4 ℃下可贮存12个月.  相似文献   

7.
This study was carried out to evaluate the influence of temperature and poultry litter on germination vegetative growth virulence and conidial production of Beauveria bassiana (Bals.) Vuill. and Metarhizium anisopliae (Metsch.) isolates on larvae and adults of the lesser mealworm (Alphitobius diaperinus) (Panzer). The vegetative growth and conidial production were evaluated on culture media. Virulence was studied submerging larvae and adults in a conidial suspension (1 x 10(8) conidia/ml). All the experiments were carried out in growth chamber (26 degrees C and 32 degrees C and 14h photophase). Fungus-killed insects were daily collected and used for microscopic conidial counts. The poultry litter effect was evaluated by submerging the insects in a fungal suspension (10(8) conidia/ml) and then transferring them to cups containing poultry litter (new and used). B. bassiana isolates were more sensitive than M. anisopliae to high temperature because conidia viability, vegetative growth and virulence were negatively affected (P < 0.05). The conidial production was higher to B. bassiana in 26 degrees C (7 to 11 x 10(8) conidia/larval cadaver and 8 x 10(8) conidia/adult cadaver) (P < 0,05). Larval stage was about 10 times more sensitive to M. anisopliae at 26 degrees C than adults stage. Regarding B. bassiana, differences on sensitivity between larval stages and adults were not observed at this temperature. However, at 32 degrees C, larval stage was more sensitive for CB116 and UEL50 isolates. Mortality was higher when larvae and adults (15.7 and 66.7% respectively) were treated by B. bassiana and maintained on new poultry litter at 26 degrees C) (P < 0.05).  相似文献   

8.
The pathogenicity of 13 isolates of Metarhizium anisopliae and two isolates of Beauveria bassiana to Ceratitis capitata and Ceratitis var. rosa fasciventris exposed as late third instar larvae in sand was evaluated in the laboratory. All isolates caused a significant reduction in adult emergence and a corresponding large mortality on puparia of both species. All isolates also induced large deferred mortality in emerging adults following treatment as late third instar larvae. On C. capitata , seven isolates ( M. anisopliae ICIPE 18, 20, 32, 60 and 69 and B. bassiana ICIPE 44 and 82) caused significantly higher mortality on puparia than other isolates. With the exception of ICIPE 32, the other four isolates of M. anisopliae above were the most pathogenic against C. r. fasciventris . Dose-response study carried out with these isolates of M. anisopliae on the two species of flies above plus another species, Ceratitis cosyra showed that the dose-mortality regression lines of ICIPE 18 and 20 were steeper with lower LC 50 values when compared with ICIPE 60 and 69 on the three species. When these two isolates were evaluated with regard to their pathogenicity to different pupal age, adult emergence was found to increase with increasing pupal age with a corresponding decrease in mortality in puparia and emerging adults in the three species of fruit flies. M. anisopliae ICIPE 18 and 20 were equally pathogenic to all pupal ages tested in C. capitata and C. cosyra but ICIPE 18 was more pathogenic to older puparia of C. r. fasciventris than ICIPE 20. Our results suggest that soil inoculation with M. anisopliae under mango trees might form an important component of integrated pest management strategies in areas where these three species of fruit fly coexist.  相似文献   

9.
W. Riedel  T. Steenberg 《BioControl》1998,43(2):175-188
Autumn-collected Bembidion lampros and Agonum dorsale were kept outdoors under semi field conditions to determine winter mortality. On three occasions (autumn, mid-winter and late winter) sub-samples of the population were incubated in the laboratory at room temperature and mortality was recorded. Generally the mortality was low in autumn and mid-winter, not exceeding 5%. A more pronounced post-winter mortality of up to 30% was observed at the end of hibernation. Only a negligible number were infected by the entomopathogenic fungi Beauveria bassiana and Paecilomyces farinosus. Infection experiments with B. bassiana isolates from Sitona lineatus, Tachyporus hypnorum and three species of ground beetles showed a similarly low susceptibility of B. lampros and A. dorsale to B. bassiana and, although Tachyporus spp. showed a distinct mycophagy and a significantly higher mortality, this could not be related to mycosis.  相似文献   

10.
We analyzed sequences of the divergent domain at the 5' end of the large subunit rRNA gene from the mitosporic entomopathogenic fungi Paecilomyces sp., Paecilomyces fumosoroseus, Paecilomyces farinosus, Paecilomyces lilacinus, Verticillium lecanii, Verticillium psalliotae, Beauveria bassiana, Aschersonia sp., Aschersonia placenta, ascomycetous Cordyceps sp., and Cordyceps militaris. Phylogenetic analysis showed P. fumosorseus as the best characterized out of the analyzed species with the B. bassiana clade as its sister group. Two of the P. farinosus isolates were invariably placed within the Verticillium cluster, which also contained C. militaris. The only analyzed P. lilacinus isolate appeared on the root of the hyphomycetous fungi and was characterized as the most distinct from all the hyphomycetous fungi tested. Polyphyly of the genus Paecilomyces was well supported by the Kishino-Hasegawa test. In all trees based on the small subunit rRNA gene sequences obtained from the GenBank, V. lecanii, V. psalliotae, P. fumosoroseus, P. tenuipes and B. bassiana form, together with that of C. militaris, the best supported cluster in the tree. The rest of Cordyceps spp. constitute a distinct clade. Phylogenetic relationships derived from both tested DNA regions show polyphyly of the genus Paecilomyces and close relationships among entomopathogenic species of the genera Verticillium, Paecilomyces, and Beauveria.  相似文献   

11.
Two exotic fungal isolates, one of Beauveria bassiana (268–86) and another of Metarhizium anisopliae (100–82), three local isolates of B. bassiana (isolates I, II, III) and one of the entomogenous bacteria Serratia marcescens, were tested for pathogenicity against the banana weevil Cosmopolites sordidus. All four isolates of B. bassiana and the one of M. anisopliae were found to be pathogenic to third—instar larvae of C. sordidus, causing mortalities of 98–100% by 9 days post—exposure to dry fungal spores. M. anisopliae was the least pathogenic to larvae with LT50 of 4.2 days, compared to 3.5, 3.3, 3.6 and 4.0 respectively for isolates I, II, III and 268–86. B. bassiana was also pathogenic to adult C. sordidus, causing mortalities varying from 63–97% by 35 days post—exposure depending on isolate. As for larvae M. anisopliae exhibited low pathogenicity for the adult C. sordidus. In general, all the fungi tested were less pathogenic to adult weevils (LT50 = 17.5; 12.5; 8.0 and 22.0 days) for isolates I, II, III and 268–86 respectively, while isolate 100–82 failed to kill 50% of adults even by 35 days post—exposure. Incubation of dead weevils in a moist environment led to development of surface mycelia starting from intersegmental junctions. Histopathology revealed extensive destruction of internal organs by hyphae which invaded most of the organs. The LT50 for S. marcescens against C. sordidus larvae was 2.8 days. However, the bacterium did not kill adult C. sordidus even at 10 times the concentration applied on larvae.  相似文献   

12.
Macedonia is an endemic region of cattle as well as of sheep and goat piroplasmosis In cattle, Theileria orientalis (=T. buffeli?), the agent of Eurasian benign theileriosis, is the most common and widespread piroplasm species. T. annulata, the agent of tropical theileriosis, seems to be rare and limited to few foci, but causes very severe clinical cases, especially in imported pure-bred or cross-bred animals. Babesia bovis and B. bigemina are present in several localities, and often coexist. Cattle babesiosis cases are due to both piroplasms, but B. bovis is considered responsible for the severe and acute clinical cases. Ovine and caprine babesiosis is due to B. ovis and mainly affected imported animals as well as indigenous animals which have been transported from localities where the infection was absent. B. ovis is extremely widespread in both sheep and goats. During the last decades, no clinical cases of small ruminant theileriosis have been registered in this region. However, T. ovis, a non-pathogenic theileria, is common in sheep, but not in goats. Anaplasma ovis, a protobacterium of small ruminants, is also present in the region.  相似文献   

13.
B.E. Urtz and W.C. Rice. 1997. Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) was used to examine the genetic variability among Beauveria bassiana isolates from infected rice water weevil (RWW), Lissorhoptrus oryzophilus , collected in south-western Louisiana. Most of the B. bassiana isolates tightly clustered into one or the other of two groups that diverged at the 65% similarity level. Three soil isolates also clustered within the two groups while one soil isolate did not tightly cluster (mean similarity = 65%) with any of the RWW isolates. The results suggest that certain genotypes of B. bassiana commonly infect RWW while others do not.  相似文献   

14.
The pathogenicity of five species of entomopathogenic fungi (Deuteromycetes, species: Beauveria bassiana, Metarhizium anisopliae, Metarhizium flavoviride, Paecilomyces fumosoroseus and Verticillium lecanii ) to the various developmental stages of Boophilus annulatus ticks was compared under laboratory conditions. M. anisopliae and B. bassiana strains were most virulent to engorged females and caused 85-100% mortality within 7-10 days post-inoculation (PI). The highest mortality of engorged females caused by other fungi reached only 25-60%. All tested fungi prevented or reduced the egg laying capability of the ticks several days before their death. Females surviving after treatment with the most virulent M. anisopliae strain (Ma-7) reached only 7-8% of their egg laying capacity as compared with the control. Other fungi caused a reduction of the weight of laid eggs by 35.4-80.8% as compared with untreated females. Only M. anisopliae and B. bassiana strains caused 70-98% mortality of the treated eggs. Unfed larvae of Boophilus annulatus were sensitive to M. anisopliae and M. flavoviride strains. The Ma-7 strain was most virulent to unfed larvae, with a mortality rate of 80.4% at a concentration of 1 ×107 spores ml -1 and 100% mortality at a concentration of 1 ×108 spores ml -1 .  相似文献   

15.
The efficacy of 13 isolates of entomopathogenic fungi belonging to Beauveria , Metarhizium or Paecilomyces spp. was assessed against Sitophilus zeamais (Coleoptera: Curculionidae) and Prostephanus truncatus (Coleoptera: Bostrichidae) using a total immersion bioassay technique in the laboratory. Fungi were applied at concentrations of 1 ×10 7 and 1 ×10 8 conidia mL -1 for P. truncatus and S. zeamais , respectively. All isolates tested were virulent to P. truncatus (98-100% mortality, and median survival time (MST) ranged from 2.85-4.05 days). Metarhizium anisopliae and B. bassiana were also virulent to S. zeamais (92-100% mortality, MST ranged from 3.58-6.28 days). The isolate of Paecilomyces sp. was found to be the least virulent against S. zeamais , causing only 26.32 ±4.29% mortality with MST of 10.38 ±0.29 days. P. truncatus proved more susceptible to the entomopathogenic fungi tested than S. zeamais . One M. anisopliae (PPRC-EE) and three B. bassiana isolates (PPRC-HH, PPRC-9609 and PPRC-9614) were selected for further study and dose-mortality relationships were assessed on S. zeamais . The tested concentrations ranged from 1 ×10 4 -1 ×10 7 conidia mL -1 . M. anisopliae (PPRC-EE) showed the lowest LC 50 (3.39 ×10 5 conidia mL -1 ) followed by B. bassiana PPRC-HH (2.04 ×10 6 conidia mL -1 ). PPRC-9609 and PPRC-9614 showed slight differences in LC 50 but not at LC 90 . The results revealed the higher potency of M. anisopliae as compared with the B. bassiana isolates tested. The study suggests that the use of entomopathogenic fungi may hold promise as an alternative method to control pests of stored-products in Ethiopia.  相似文献   

16.
Wildlife reservoir species and genetic diversity of Anaplasma ovis (Rickettsiales: Anaplasmataceae) have been poorly characterized. Bighorn sheep (Ovis canadensis), captured in Montana from December 2004 to January 2005, were tested for antibodies to Anaplasma spp.; the presence of A. ovis was determined by the characterization of major surface protein msp4 sequences. Anaplasma antibodies were detected in 25/180 (14%) sampled bighorn sheep and A. ovis msp4 sequences were amplified by polymerase chain reaction (PCR) and sequenced from 9/23 (39%) of seropositive animals. All animals were negative by PCR for the related pathogens, Anaplasma phagocytophilum and Anaplasma marginale. All msp4 sequences identified in the bighorn sheep were identical and corresponded to a single A. ovis genotype that was identical to a sheep isolate reported previously from Idaho. The finding of a single genotype of A. ovis in this wild herd of bighorn sheep was in contrast to the genetic diversity reported for A. marginale in cattle herds in the western United States and worldwide. These results demonstrated that bighorn sheep may be a wildlife reservoir of A. ovis in Montana.  相似文献   

17.
Abstract:  The two-spotted stink bug, Perillus bioculatus (F) (Hem., Pentatomidae) is considered an important predator of Colorado potato beetle egg masses and small larvae. The susceptibility of P. bioculatus second instar nymphs to six isolates of Beauveria bassiana (Balsamo) Vuillemin, which are highly pathogenic to Colorado potato beetle, was tested in the laboratory. Five isolates were highly pathogenic and caused more than 77% mortality after 8 days at a concentration of 106 conidia/ml. However, isolate IPP46 showed low pathogenicity and caused only 11% mortality of nymphs. The pathogenicity of isolates was independent of their host, source or country of origin. Isolate IPP46 was tested at six different concentrations. A linear relationship between the concentration of B. bassiana and the mortality of nymphs was observed. The 50% lethal concentration (LC50) value was 3.4 × 107 conidia/ml. The LT50 decreased with increase of conidia concentration used. The present results suggest that isolate IPP46 has good potential as a biological control agent within an integrated pest management programme.  相似文献   

18.
The pathogenicity of Vespula vulgaris wasp workers and larvae to a range of fungi was determined. All fungi were isolated in New Zealand and included isolates from Vespula, known generalist insect pathogens, and isolates generally nonpathogenic to insects. Workers and larvae were highly susceptible to pathogenic isolates at high spore concentrations (>1.75 x 10(5) cfu/individual). Eight isolates, two of Metarhizium anisopliae, five of Beauveria bassiana, and one of Aspergillus flavus were pathogenic while a single isolate of M. flavouiride var. novazealandicum, Cladosporium sp., and Paecilomyces sp. were not. The transfer of spores between workers, and between workers and larvae, was also investigated using several different application methods. Transfer of spores occurred between treated and untreated individuals, and for some of the application methods sufficient spores were transferred to cause mortality of the nontreated individuals. These findings are related to the potential of fungi for the control of wasps.  相似文献   

19.
The occurrence and abundance of entomopathogenic fungi were analysed in 203 soil samples of the Moroccan endemic forests of Argania spinosa, the world main refuge of the Mediterranean fruit fly, Ceratitis capitata. Using the Galleria baiting method and selective media, entomopathogenic fungi were isolated from 186 of the 203 (91.62%) soil samples, with only three species found: Beauveria bassiana (Balsamo) Vuillemin, Metarhizium anisopliae (Metschnikoff) Sorokin and Paecilomyces lilacinus (Thom.) Samson. B. bassiana was the most widespread entomopathogenic fungi (90.64%) in the Argan forest whereas M. anisopliae was less common (15.27%) and P. lilacinus was very rare (1.48%). This is the first report of natural occurrence of M. anisopliae and P. lilacinus in Morocco. Furthermore, 118 Moroccan B. bassiana isolates were studied for their pathogenicity to C. capitata and thermotolerance. Most of these autochtonous B. bassiana isolates were virulent (86.44%) to Medfly pupae and tolerant (55.08%) to temperature stress at 45°C for 2 h. Only 60.17% of Moroccan B. bassiana isolates might be considered as highly entomopathogenic and will serve as a source of potential biological control agents to C. capitata. The percentage of thermotolerant and pathogenic B. bassiana to C. capitata were shown to decrease significantly at winter time characterized by low temperatures and absence of any noticeable medfly in the Argan forest. The occurrence, thermotolerance and virulence of B. bassiana isolates to C. capitata seemed to be related to the sampling periods and location. Our data are discussed with respect to fungal ecology and biocontrol potential of B. bassiana isolates in relation to their habitat.  相似文献   

20.
琅琊山虫生真菌物种多样性和季节变化   总被引:1,自引:0,他引:1  
在皖东琅琊山自然保护区设置的20个样方中共采集672份虫生真菌标本,分属于4科8属20种.优势种依次为球孢白僵菌、粉拟青霉、环链拟青霉、布氏白僵菌和玫烟色拟青霉,其中球孢白僵菌占绝对优势,相对多度高达73.8%.选用物种多度、Shannon-Wiener指数H′和Pielou均匀度E对琅琊山虫生真菌物种多样性和季节分布进行研究发现,虫生真菌数量丰富但物种多样性指数较低;夏季虫生真菌菌株最为丰富,均匀度相对较低,随着气温及降雨量的下降,菌株数量急剧下降,均匀度相对较高;不同季节白僵菌属的数量波动大,但拟青霉属波动较小.  相似文献   

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