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1.
Twenty-three isolates of Metarhizium anisopliae (Metschnikoff) Sokorin and three isolates of Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales: Clavicipitaceae) were assessed for their virulence against the two-spotted
spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). Based on the screening results, nine isolates of M. anisopliae and two isolates of B. bassiana were tested for their virulence against young adult (1- to 2-day-old) female T. urticae at constant temperatures of 20, 25, 30 and 35°C. At all temperatures tested, all the fungal isolates were pathogenic to T. urticae but mortality varied with isolates and temperatures. Fungal isolates were more virulent at 25, 30 and 35°C than at 20°C.
The lethal time to 50% mortality (LT50) and lethal time to 90% mortality (LT90) values decreased with increased temperature. There were no significant differences in virulence between fungal isolates
at 30 and 35°C; however, significant differences were observed at 20 and 25°C. 相似文献
2.
【目的】测定金龟子绿僵菌(Metarhizium anisopliae)对斜纹夜蛾(Spodoptera litura) 2龄幼虫的毒力,研究金龟子绿僵菌侵染后寄主体内抗氧化酶活性和肠道内细菌群落的变化,探讨斜纹夜蛾对金龟子绿僵菌侵染的防御机制。【方法】采用浸渍法测定不同浓度金龟子绿僵菌对斜纹夜蛾2龄幼虫的毒力;应用IlluminaMiSeq高通量测序技术测定肠道细菌群落。【结果】不同浓度的孢悬液对斜纹夜蛾2龄幼虫均有一定的毒力,处理7 d时半致死浓度(LC50)为3.944 107个孢子/mL;浓度为1.0×109个孢子/mL时,半致死时间最短(LT50)为4.6 d,校正后的死亡率为81.03%。处理后未致死的斜纹夜蛾幼虫体内抗氧化酶活性显著高于对照组。处理后致死的斜纹夜蛾幼虫肠道细菌群落多样性显著高于对照组;且处理后致死的斜纹夜蛾幼虫肠道细菌群落组成与对照组差异显著。【结论】金龟子绿僵菌对斜纹夜蛾幼虫的致死率和致死效率与金龟子绿僵菌的浓度呈正相关;斜纹夜蛾幼虫体内的抗氧化酶可能在抵抗金龟子绿僵菌侵染的过程中起重要作... 相似文献
3.
Pallavi B. Nahar Shuklangi A. Kulkarni Mahesh S. Kulye Santosh B. Chavan Girish Kulkarni Armugham Rajendran 《Biocontrol Science and Technology》2008,18(4):337-355
The effect of repeated conidial sub-culturing of Metarhizium anisopliae on its virulence against Helicoverpa armigera (Hübner) was studied. The LT50 observed against third instar larvae of H. armigera for the first sub-culture was 3.4 days; it increased to 4.5 and 5.6 days for the 20th and the 40th sub-cultures, respectively. The LT50 values after passage of the 40th sub-culture on H. armigera decreased to 4.4 and 3.7 days for the 40th (first in vivo) and the 40th (fifth in vivo) passages, respectively. Similarly, the LC50 of M. anisopliae towards third instar larvae of H. armigera increased from the first sub-culture (0.17×104) to (3.0×104) for the 40th conidial transfers on potato dextrose agar and again decreased to 0.74×104 and 0.23×104 in the 40th (first in vivo) and the 40th (fifth in vivo) passage, respectively. Similar trends for LC50 and LT50 values were seen when sugarcane woolly aphid, Ceratovacuna lanigera Zehntner was used as a host. Significant variation in appressorium formation and cuticle-degrading enzyme production such as chitinase, chitin deacetylase, chitosanase and protease during subsequent sub-culturing and passage through H. armigera was observed. Though there was no effect on internal transcribed spacer (ITS) sequence pattern, interestingly, in randomly amplified polymorphic DNA (RAPD), significant differences in the band intensities and in the banding pattern for different sub-cultures of M. anisopliae were observed. As stable virulence towards the insect pest is desirable for commercialisation of a mycoinsecticide, such changes in virulence due to repeated in vitro transfer need to be monitored and minimised. 相似文献
4.
Weiguo Fang Jin Feng Yanhua Fan Michael J. Bidochka Yan Pei 《Journal of invertebrate pathology》2009,102(2):155-159
Entomopathogenic fungi, such as Beauveria bassiana and Metarhizium anisopliae are being developed as alternatives to chemical insecticides. They infect insects by direct penetration of the cuticle using a combination of physical pressure and extracellular hydrolytic enzymes such as proteases and chitinases. Previously we found that overexpression of a subtilisin-like protease (Pr1A) or a chitinase (Bbchit1) resulted in increased virulence of M. anisopliae and B. bassiana, respectively. In this study, we found that a mixture of the B. bassiana Pr1A homolog (CDEP1) and Bbchit1 degraded insect cuticle in vitro more efficiently than either CDEP1 or Bbchit1 alone. Based on this we produced three plasmid constructs; (1) Bbchit1, (2) CDEP1, and (3) a fusion gene of Bbchit1 linked to CDEP1 each under the control of the constitutive gpd promoter from Aspergillus nidulans. B. bassiana transformants secreting the fusion protein (CDEP1:Bbchit1) penetrated the cuticle significantly faster than the wild type or transformants overexpressing either Bbchit1 or CDEP1. Compared to the wild type, the transformant overexpressing CDEP1 showed a 12.5% reduction in LT50, without a reduction in LC50. The LT50 of the transformant expressing CDEP1:Bbchit1 was reduced by 24.9%. Strikingly, expression of CDEP1:Bbchit1 resulted in a 60.5% reduction in LC50, more than twice the reduction obtained by overexpression of Bbchit1 (28.5%). This work represents a significant step towards the development of hypervirulent insect pathogens for effective pest control. 相似文献
5.
Sunday Ekesi Abubakar D. Akpa Isa Onu Michael O. Ogunlana 《Archives Of Phytopathology And Plant Protection》2013,46(2):171-180
The pathogenicity of four isolates each of the entomopathogenic fungi, Beauveria bassiana (Bals.) Vuill. and Metarhizium anisopliae (Metsch.) Sorok. to apterous adult Aphis craccivora Koch was evaluated in the laboratory at 4 concentrations of conidia. All fungi isolates tested were found to be pathogenic to the insect but their virulence varied among species and isolates within species. Three isolates, B. bassiana CPD 11 and M. anisopliae CPD 4 and 5 caused significantly higher mortality than the other isolates at the various concentrations tested causing mortality of between 58–91%, 64 to 93% and 66–100%, respectively, at 7 days post treatment. At the highest concentration of 1 × 108conidiaml‐1, these isolates produced the shortest LT50s of 3.5, 3.6 and 3.4 days, respectively. Their LC50s were 6.8 × 105, 3.1 × 105 and 2.7 × 105 conidia ml‐1, respectively. The results indicate that these isolates are promising candidates for the control of the cowpea aphid but their pathogenicity to various aphid non‐target beneficial organisms within the cowpea agroecosystem warrant further investigation before initiating field control. 相似文献
6.
María Guadalupe Maldonado-Blanco Johanna Lizzette Gallegos-Sandoval Gabriela Fernández-Peña Carlos Francisco Sandoval-Coronado Myriam Elías-Santos 《Biocontrol Science and Technology》2014,24(2):180-189
Three Metarhizium anisopliae and three Beauveria bassiana isolates were cultivated in media containing casamino acids, soybean flour or sunflower seed flour and were shaken for three days. M. anisopliae presented similar yields of around 106 submerged spores/ml without significant differences among them, whereas B. bassiana produced yields of around 108 spores/ml, of which GHA strain produced more submerged spores in the casamino acids medium. The other two strains showed no significant difference in the production of submerged spores in the three media used. Differences in mortality on Aedes aegypti larvae were observed with the submerged spores of Metarhizium depending on isolate and medium used. M. anisopliae 2157 caused significantly higher mortality (40%) when cultivated in casamino acids medium. It presented an LC50 of 8.93 × 105 submerged spores/ml water against mosquito larvae five days after application, whereas it caused 27% mortality in Ae. aegypti adults 10 days after application. In conclusion, fungal nutrition affected virulence of some isolates of M. anisopliae against Ae. aegypti larvae while such an effect was not noted for B. bassiana isolates. 相似文献
7.
Thomas Bawin Fawrou Seye Slimane Boukraa Jean-Yves Zimmer Fara Nantenaina Raharimalala Quentin Zune 《Biocontrol Science and Technology》2016,26(5):617-629
The spore productivity and insecticidal activity of two opportunistic insect pathogenic Aspergillus species (namely: Aspergillus clavatus Desmazieres and Aspergillus flavus Link (Ascomycota: Eurotiales, Trichocomaceae)) were compared to Metarhizium anisopliae sensu lato (Metchnikoff) Sorokin (Ascomycota: Hypocreales, Clavicipitaceae) for mosquito (Diptera: Culicidae) control. The production of aerial spores on wheat bran and white rice was investigated in solid-, semi-solid-, and liquid-state media supplemented with a nutritive solution. Wheat bran-based media increased the spore yield in solid-state from three to sevenfold: A. clavatus produced 48.4?±?5.2 and 15.7?±?1.6?×?108 spores/g, A. flavus produced 22.3?±?4.1 and 3.1?±?2.5?×?108 spores/g, and M. anisopliae produced 39.6?±?6.5 and 13.1?±?2.6?×?108 spores/g of wheat bran or white rice, respectively. A. clavatus, A. flavus and M. anisopliae spores harvested from wheat bran-based solid-state media showed lethal concentrations (LC50) of 1.1, 1.8, and 1.3?×?108 spores/ml against Culex quinquefasciatus Say larvae in 72?h. Because A. clavatus and M. anisopliae displayed similar features when cultured under these conditions, our results suggest that insect pathogenic Aspergillus species may be as productive and virulent against mosquito larvae as a well-recognised entomopathogenic fungus. 相似文献
8.
Vitalis W. Wekesa Nguya K. Maniania Markus Knapp Hamadi I. Boga 《Experimental & applied acarology》2005,36(1):41-50
Seventeen isolates of Metarhizium anisopliae (Metschnikoff) Sorokin and two isolates of Beauveria bassiana (Balsamo) Vuillemin were evaluated for their pathogenicity against the tobacco spider mite, Tetranychus evansi Baker & Pritchard. In the laboratory all the fungal isolates were pathogenic to the adult female mites, causing mortality between 22.1 and 82.6%. Isolates causing more than 70% mortality were subjected to dose–response mortality bioassays. The lethal concentration causing 50% mortality (LC50) values ranged between 0.7×107 and 2.5×107 conidia ml−1. The lethal time to 50% mortality (LT50) values of the most active isolates of B. bassiana and M. anisopliae strains varied between 4.6 and 5.8 days. Potted tomato plants were artificially infested with T. evansi and treated with B. bassiana isolate GPK and M. anisopliae isolate ICIPE78. Both fungal isolates reduced the population density of mites as compared to untreated controls. However, conidia formulated in oil outperformed the ones formulated in water. This study demonstrates the prospects of pathogenic fungi for the management of T. evansi. 相似文献
9.
Karla Tatiana Murillo-Alonso Victor Manuel Hernández-Velázquez Paz María Salazar-Schettino Margarita Cabrera-Bravo 《Biocontrol Science and Technology》2019,29(5):466-477
The entomopathogenic fungus Metarhizium anisopliae is virulent for the insect triatomine Meccus pallidipennis. To evaluate the functionality of a fungal formulation (vegetable oil and emulsifiers) of this fungus, virulence was assayed by insect mortality on the pronotum of third instar nymphs (N3) M. pallidipennis in laboratory conditions and ST50 was calculated. Mortality was evaluated directly: 100%, 97.33% and 98.66% mortalities were caused by formulation, emulsified formulation and fungal conidia, respectively, at day 8 of insect infection. Another bioassay was carried out in simulated external conditions (peridomicility) using red and gray brick walls, a stone fence and mountain soil (experimental units). These simulated conditions were infected with 10?ml of a 1?×?109?conidia/ml emulsified formulation by means of a manual sprinkler prior to the placement of the nymphs. Ten N3 M. pallidipennis were deposited in each experimental unit and insect mortality was monitored every 12?h for 22 days. Each treatment was replicated four times. With the red brick wall, a mortality of 90% at day 22 and a ST50 of 15 days were obtained on N3 M. pallidipennis; with the gray brick wall, 100% mortality and a ST50 of 13 days; and with the stone fence, 88.33% mortality and a ST50 of 21 days. The results obtained in this research work indicate that the formulation with conidia of the M. anisopliae strain EH-473/4 may be auxiliary in the development of strategies for the control of Chagas disease insect transmitters such as M. pallidipennis. 相似文献
10.
Selection of promising fungal biological control agent of the western flower thrips Frankliniella occidentalis (Pergande) 总被引:1,自引:0,他引:1
Niassy S Maniania NK Subramanian S Gitonga LM Mburu DM Masiga D Ekesi S 《Letters in applied microbiology》2012,54(6):487-493
Aims: Larval stages of Frankliniella occidentalis are known to be refractory to fungal infection compared with the adult stage. The objective of this study was to identify promising fungal isolate(s) for the control of larval stages of F. occidentalis. Methods and Results: Ten isolates of Metarhizium anisopliae and eight of Beauveria bassiana were screened for virulence against second‐instar larvae of F. occidentalis. Conidial production and genetic polymorphism were also investigated. Metarhizium anisopliae isolates ICIPE 7, ICIPE 20, ICIPE 69 and ICIPE 665 had the shortest LT50 values of 8·0–8·9 days. ICIPE 69, ICIPE 7 and ICIPE 20 had the lowest LC50 values of 1·1 × 107, 2·0 × 107 and 3·0 × 107 conidia ml?1, respectively. Metarhizium anisopliae isolate ICIPE 69 produced significantly more conidia than M. anisopliae isolates ICIPE 7 and ICIPE 20. Internally transcribed spacers sequences alignment showed differences in nucleotides composition, which can partly explain differences in virulence. Conclusion: These results coupled with the previous ones on virulence and field efficacy against other species of thrips make M. anisopliae isolate ICIPE 69 a good candidate. Significance and Impact of the Study: Metarhizium anisopliae isolate ICIPE 69 can be suggested for development as fungus‐based biopesticide for thrips management. 相似文献
11.
Conidial spores are often used as the infectious agent during insect biocontrol applications of entomopathogenic fungi. Here we show differential virulence of conidia derived from Metarhizium anisopliae strain EAMa 01/58-Su depending upon the solid substrata used for cultivation, where LC50 values differed by up to ~10-fold (5.3×106?4.5×105 conidia/ml) and LT50 values by ~40% (9.8?7.1 d). This fungal strain is also known to secrete proteins that are toxic towards adult Mediterranean fruit flies, Ceratitis capitata, and the Greater wax moth, Galleria mellonella, larvae. In vitro production and intrahemoceol injection using G. mellonella as the host was used to test fractions during purification of the protein toxins, demonstrating that they elicited defence-related responses including melanisation and tissue necrosis. Production of these proteins/peptides along with a number of potential cuticle degrading enzymes was confirmed both in vitro and during the infection process (in vivo). Two-dimensional gel electrophoresis, followed by gel elution and bioassay, was used to identify at least three proteins or peptides (molecular mass=11, 15 and 15 kDa) as mediating the observed insect toxicity. These data demonstrate that in vitro screening for insect toxins can mimic in vivo (i.e. during the infection process) secretion and applies the use of proteomics to invertebrate pathology. 相似文献
12.
Seventeen isolates of Metarhizium anisopliae (Metschnikoff) Sorokin and two isolates of Beauveria bassiana (Balsamo) Vuillemin were evaluated for their pathogenicity against the tobacco spider mite, Tetranychus evansi Baker & Pritchard. In the laboratory all the fungal isolates were pathogenic to the adult female mites, causing mortality between 22.1 and 82.6%. Isolates causing more than 70% mortality were subjected to dose–response mortality bioassays. The lethal concentration causing 50% mortality (LC50) values ranged between 0.7×107 and 2.5×107 conidia ml−1. The lethal time to 50% mortality (LT50) values of the most active isolates of B. bassiana and M. anisopliae strains varied between 4.6 and 5.8 days. Potted tomato plants were artificially infested with T. evansi and treated with B. bassiana isolate GPK and M. anisopliae isolate ICIPE78. Both fungal isolates reduced the population density of mites as compared to untreated controls. However, conidia formulated in oil outperformed the ones formulated in water. This study demonstrates the prospects of pathogenic fungi for the management of T. evansi. 相似文献
13.
Adriano Rodrigues de Paula Eliane Souza Brito César Ronald Pereira Marinete Pinheiro Carrera 《Biocontrol Science and Technology》2008,18(10):1017-1025
Dengue fever vectored by the mosquito Aedes aegypti is one of the most rapidly spreading insect-borne diseases, stimulating the search for alternatives to current control methods. Screening assays using a range of Metarhizium anisopliae and Beauveria bassiana isolates were performed against adult female Ae. aegypti. Four virulent isolates were selected for detailed study. Adult female mosquitoes were exposed to supports previously inoculated with fungal suspensions. Fungal isolates were suspended in Tween 80+8% vegetable oil. The isolates caused between 70 and 89% mortality as a result of fungal infection over the 7-day test period. Mean survival times varied between 3 and 5 days for treated insects, whilst control survival exceeded 40 days. The most promising isolate, M. anisopliae LPP133, based not only on virulence but facility for mass production, was used for lethal exposure time determinations. An exposure time of only 3.5 h was necessary to cause 50% mortality. Large cage trails were also carried out and mean survival time of insects exposed to fungus impregnated black cloths was significantly reduced. These results show that entomopathogenic fungi could be promising biological control agents for use against adult Ae. aegypti, by inoculating fungi onto surfaces on which the mosquitoes tend to rest. The subsequent mortality caused by the fungi could potentially reduce the populations of this insect thus reducing the incidence of Dengue. 相似文献
14.
Genetic variability in a putative virulence factor, the neutral trehalase (Ntl) gene, was examined in strains of the insect pathogenic fungi Metarhizium anisopliae and Metarhizium flavoviride by restriction fragment length polymorphism (RFLP). The Ntl gene was sequenced from four of these strains that showed dissimilar RFLP patterns. Enzyme kinetic experiments were also performed on the partially purified neutral trehalase in order to assess whether nucleotide changes in these strains related to differences in enzyme catalytic function (i.e., K
m
, V
max, and K
cat). Finally, the Metarhizium strains were assessed in bioassays against waxworm larvae in order to relate nucleotide variation with Ntl enzyme kinetics and insect virulence. The greatest RFLP variation was observed with Rsa1. M. flavoviride was found to be most dissimilar in RFLP patterns when compared with the M. anisopliae strains. RFLP patterns for Ntl were diagnostic markers for previously studied genetic groups of M. anisopliae. Comparisons of Ntl sequences showed that the introns were found to be more variable (6.2%) than the exons (3.1%). Comparisons of the translated nucleotide codons showed high levels (91%) of synonymous sequence variation between strains. Another fraction of the remaining mutations was neutral, resulting in amino acid substitutions with similar functions. The neutral trehalase was partially purified by preparative isoelectric focus, revealing a single band of enzyme activity as assessed by analytical isoelectric focusing (pI ca. 5). Kinetic properties of the neutral trehalases revealed no differences between the M. anisopliae strains, while the M. flavovoride had a lower K
cat/K
m
. However, there was lower virulence in one strain that showed Ntl enzyme kinetic properties that were similar to the other strains, suggesting that factors other than neutral trehalase may be responsible for delimiting virulence in this insect pathogenic fungi. Although there is nucleotide variation in genes involved in pathogenicity, this variation is mostly neutral in nature, and there is strong stabilizing selection to maintain enzyme function. 相似文献
15.
Drauzio E. N. Rangel Aquiles E. Piedrabuena Isaac Roitman Claudio L. Messias 《Archives of insect biochemistry and physiology》2020,105(4):e21745
Chagas disease is one of the most important insect-vectored diseases in Brazil. The entomopathogenic fungus Metarhizium anisopliae was evaluated against nymphs and adults of Panstrongylus megistus, Triatoma infestans, and T. sordida. Pathogenicity tests at saturated humidity demonstrated high susceptibility to fungal infection. The shortest estimates of 50% lethal time (LT50) for P. megistus varied from 4.6 (isolate E9) to 4.8 days (genetically modified strain 157p). For T. infestans, the shortest LT50 was 6.3 (E9) and 7.3 days (157p). For T. sordida, the shortest LT50 was 8.0 days (157p). The lethal concentration sufficient to kill 50% of T. infestans (LC50) was 1.9 × 107 conidia/ml for strain 157p. In three chicken coops that were sprayed with M. anisopliae, nymphs especially were well controlled, with a great population reduction of 38.5% after 17 days. Therefore M. anisopliae performed well, controlling Triatominae in both laboratory and field studies. 相似文献
16.
I. Oguz Ozdemir Rahman Kushiyev Ismail Erper Celal Tuncer 《Archives Of Phytopathology And Plant Protection》2013,46(5-6):470-480
AbstractIn this study, Metarhizium anisopliae TR 106 and Beauveria bassiana TR 217 was tested against fourth instar larvae of Thaumetopoea pityocampa. The LT50 and LT90 of 1?×?106 concentration of M. anisopliae against T. pityocampa were 3.60 and 4.11 for direct application, while these were 2.87 and 3.60?days, respectively in leaves application. The LT50 and LT90 of the 1?×?108 concentration of the same isolate were 2.50 and 2.95?days for direct application, and 2.98 and 3.74?days for leaves application. The LT50 of insect and leaves application for 1?×?106 of B. bassiana were 3.75 and 3.49?days, respectively. The LT90 of same concentration for insect application was 4.48?days, while LT90 for leaves application was 4.63?days. Similarly, LT50 of insect and leaves application for 1?×?108 of B. bassiana were 3.03 and 3.31?days, while LT90 were 3.68 and 4.29?days, respectively. Approximate 100% mycosis was observed in all treatments. 相似文献
17.
The PacC transcription factor regulates secondary metabolite production and stress response,but has only minor effects on virulence in the insect pathogenic fungus Beauveria bassiana
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Zhibing Luo Hui Ren Jarrod J. Mousa Drauzio E. N. Rangel Yongjun Zhang Steven D. Bruner Nemat O. Keyhani 《Environmental microbiology》2017,19(2):788-802
18.
Muhammad Yasin Waqas Wakil Muhammad Usman Ghazanfar Mirza Abdul Qayyum Muhammad Tahir Geoffrey O. Bedford 《Entomological Research》2019,49(1):3-12
Nineteen different isolates of the entomopathogenic fungi Beauveria bassiana sensu lato (s.l.) and Metarhizium anisopliae s.l. (Ascomycota: Hypocreales), recovered from different soil samples (field crops, fruit orchards, vegetable fields and forests) and insect cadavers were tested against Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) at two different spore concentrations (1 × 107 and 1 × 108 conidia mL?1). Three isolates of B. bassiana and two of M. anisopliae gave >88 % larval and >75 % adult mortality of R. ferrugineus on their highest dose rate respectively. More sporulating cadavers (mycosis) resulted from a high dose rate compared to low dose on both life stages of R. ferrugineus. The current study confirmed the lethal action of B. bassiana and M. anisopliae isolates with mortality levels usually directly proportional to the conidial concentration. This study further confirmed that the isolates recovered from R. ferrugineus dead cadavers gave more mortality compared to the other sources. In the virulence assay two isolates of B. bassiana caused the highest percentage of both larval and adult mortality at all exposure intervals which suggest that they may be the most promising for use in sustainable management programs aimed at microbial control in date palm orchards. 相似文献
19.
Ekesi S 《Mycopathologia》1999,148(3):131-139
The virulence of 8 isolates of entomopathogenic hyphomycetes against adult and 5th instar nymph of Clavigralla tomentosicollis was evaluated in the laboratory at 4 different concentrations of inoculum. At all concentrations, Beauveria bassiana CPD 9 and Metarhizium anisopliae CPD 5 caused the highest mortality in adult bug ranging from 58 to 97% and 53 to 100%, respectively at 7 days post inoculation.
The same isolates had the shortest LT50 (3.5 and 4.1 days, respectively) and the lowest LC50 (1.8 × 105 and 9.8 × 104 conidia ml-1 values in adult insects. In nymphs, M. anisopliae CPD 5 was the most virulent isolate causing mortality of between 43 to 92% with the shortest LT50 of 2.7 days and the lowest LC50of 4.6 × 105 conidia ml-1 which however did not differ significant from LC50 observed in B. bassiana CPD 9 isolate at 5 days post inoculation. A significant reduction in feeding in both developmental stages treated with fungi
was observed at 2 days after treatment with the greatest reduction occurring in insects treated with B. bassiana CPD 9 and M. anisoplia CPD 5. In adult insects treated with these isolates, some bugs ceased feeding 24 h before death. When these two isolates
were compared in caged experiment with an untreated control using a susceptible, tolerant and moderately resistant variety
of cowpea, percentage pod and seed damage were significantly lower in fungal treated cages than in the control cages on all
varieties tested. Grain yield per plant was also significantly higher in fungal treated cages than in the control cages on
all varieties. The performance of M. anisopliae CPD 5 was however superior to B. bassiana CPD 9. Application of the fungi on moderately resistant variety of cowpea was found to enhance the performance of the pathogen.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
20.
Saul Tlecuitl-Beristain Gustavo Viniegra-González Gerardo Díaz-Godínez Octavio Loera 《Mycopathologia》2010,169(5):387-394
Rice and oat flours were analyzed as media for the production of conidia by M. anisopliae var. lepidiotum. The presence of peptone increased conidia yield regardless of the substrate used; however, the highest yield was achieved
on oat flour media. The effect of oxygen on conidia production using oat-peptone medium was also studied at two levels: Normal
atmosphere (21% O2) and Oxygen-rich pulses (26% O2). Maximum conidia production (4.25 × 107 conidia cm−2) was achieved using 26% O2 pulses after 156 h of culture, which was higher than 100% relative to conidial levels under normal atmosphere. Conidia yield
per gram of biomass was 2.6 times higher with 26% O2 (1.12 × 107 conidia mg−1). Conidia quality parameters, such as germination and hydrophobicity, did not show significant differences (P < 0.05) between those treatments. Bioassays parameters, using Tenebrio molitor adults, were analyzed for conidia obtained in both atmospheres and data were fitted to an exponential model. The specific
mortality rates were 2.22 and 1.26 days−1, whereas lethal times for 50% mortality were 3.90 and 4.31 days, for 26% O2 pulses and 21% O2 atmosphere, respectively. These results are relevant for production processes since an oxygen increase allowed superior levels
of conidia by M. anisopliae without altering quality parameters and virulence toward Tenebrio molitor adults. 相似文献