Virulence of Native Isolates of Metarhizium anisopliae and Beauveria bassiana Against Helicoverpa armigera in Nepal (original) (raw)
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Formosan Entomologist, 2008
A field study was conducted to evaluate the efficacy of two most virulent native isolates of insect pathogenic fungi (Metarhizium anisopliae and Beauveria bassiana) and compared with four commercial biopesticides against Chickpea pod borer (Helicoverpa armigera Hubner) at Chitwan, Nepal. The number of H. armigera lavae observed in plots treated with M. anisopliae and B. bassiana were significantly lesser than the control plots during vegetative, flowering and pod setting stage of chickpea. Similarly, the chickpea yield was significantly higher in the plots treated with M. anisopliae and B. bassiana than control, however lesser than NPV and Bt treated plots. Based on this study, the native isolates have potential to be a biocontrol agent against the H. armigera in Nepal.
Virulence of Metarhizium anisopliae and Beauveria bassiana against Common White Grubs in Nepal
臺灣昆蟲, 2008
Entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were isolated from soils and white grubs cadavers from farmlands in Nepal. In the mortality studies, 8 isolates infected more than 80% of the grubs, another 65 isolates infected more than 50% of the grubs and the rest of the isolates had a low level of pathogenicity with 10 7 conidia/mL concentration. Five isolates were highly pathogenic against third instar larvae of Maladera affinis. The isolate, M. anisopliae M1 was the most virulent strain of all the evaluated isolates. LT 50 of the tested isolates varied between 2-9 weeks. Isolates M1 and M6 had the highest mortality rates and required the shortest time to kill the white grub larvae. Assessment with fungus inocula with conidiospores and blastospores against three different instars of white grubs showed that a significantly larger numbers of second instar larvae were infected with the fungi than first and third instars. A comparison of indigenous and commercial isolates of M. anisopliae and B. bassiana with third instar larvae of Anomala dimidiata, Adoretus lasiopygus and Phyllognathus dionysius demonstrated that native isolates were more virulent to the above three white grubs species tested than the exotic fungi. Based on this study, the indigenous virulent isolates have the potential to be biocontrol agents against white grubs in Nepal.
International Journal of Environment and Climate Change
The chickpea pod borer Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) is a destructive pest of chickpeas that is difficult to control using conventional methods. We isolated and evaluated the virulence of five isolates of Metarhizium anisopliae against larvae of H. armigera. All isolates of M. anisopliae, SVPUAT 1, SVPUAT 2, SVPUAT 3, SVPUAT 4, and SVPUAT 5, were most effective against the second instar H. armigera at 2 ×108 conidia/ml. Among all isolates, SVPUAT 1 Accession no. ON183248 had the highest virulence 100% mortality, whereas LT50 and LT90 were 3.16 and 5.16 days.
The present work aims to assess the pathogenicity of the conidia of six isolates of Metarhizium anisopliae and two isolates of Beauveria bassiana on Helicoverpa armigera in order to select the most promising ones for developing a microbiological product to be used in cotton fields. The pathogenicity of six isolates of the entomopathogenic fungi, M. anisopliae (Met 28, Met 32, Met 92, Met 31, Met 34 and Met 341) and two isolates of B. bassiana (Bb11 and Bb 12) was evaluated in the laboratory by applying topically 1 µl of an oil-based formulation of conidia at a concentration of 10 8 conidia/ml on the third, fourth, fifth and the sixth instars of H. armigera. Taken separately, each isolate caused less mortality among the larvae of the sixth stage than in younger stages. Corrected mortality rates varied from 3.6 ± 1.8 % (Met 28, sixth instar) to 56.3 ± 0.8% (Met 31, third instar) for M. anisopliae and from 3.6 ± 1.8 % (Bb 12, sixth instar) to 34.4 ± 4.2% (Bb 11, third instar) for B. bassiana. Certain isolates of Metarhizium were infective to pupa. Host development stage at inoculation affected both survival times compared to control. The results of the presented study showed that the isolates of Metarhizium (Met 31) and Beauveria (Bb 11, known as Bba 5653), the last being tested successfully against Plutella xylostella (Lepidoptera: Noctuidae), are virulent isolates and can be promising isolates for the control of the cotton bollworm H. armigera.
Virulence of Metarhizium anisopliae and Beauveria bassiana to Ctenocephalides felis felis
Annals of the New York Academy of Sciences, 2008
Entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were isolated from soils and white grubs cadavers from farmlands in Nepal. In the mortality studies, 8 isolates infected more than 80% of the grubs, another 65 isolates infected more than 50% of the grubs and the rest of the isolates had a low level of pathogenicity with 10 7 conidia/mL concentration. Five isolates were highly pathogenic against third instar larvae of Maladera affinis. The isolate, M. anisopliae M1 was the most virulent strain of all the evaluated isolates. LT 50 of the tested isolates varied between 2-9 weeks. Isolates M1 and M6 had the highest mortality rates and required the shortest time to kill the white grub larvae. Assessment with fungus inocula with conidiospores and blastospores against three different instars of white grubs showed that a significantly larger numbers of second instar larvae were infected with the fungi than first and third instars. A comparison of indigenous and commercial isolates of M. anisopliae and B. bassiana with third instar larvae of Anomala dimidiata, Adoretus lasiopygus and Phyllognathus dionysius demonstrated that native isolates were more virulent to the above three white grubs species tested than the exotic fungi. Based on this study, the indigenous virulent isolates have the potential to be biocontrol agents against white grubs in Nepal.
Comparative vulnerability of Helicoverpa armigera (Hubner) larvae to selected entomopathogenic fungi
Journal of Entomology and Zoology Studies, 2021
The larvae of Helicoverpa armigera (Hubner), (Lepidoptera: Noctuidae), a polyphagous pest affecting different crops in India, were treated with variable concentrations of conidia of two soil isolates and two commercially available entomopathogenic fungi belonging to two species, Beauveria bassiana (Balsamo-Crivelli) Vuillemin and Metarhizium anisopliae (Metschnikoff) in a laboratory. The suspension of conidia (109 conidia/ml) collected from Sabouraud dextrose agar media with yeast extract (SDAY) plates resulted in the highest mortality (98.3%) with Beauveria bassiana (PSC-13) and the lower mortality (75%) with Metarhizium anisopliae (Ag-CM). Using the larval immersion method, the values of LC50 and LC90 reveal that Beauveria bassiana was the most virulent species while Metarhizium anisopliae was the less virulent species in between the entomopathogenic fungi used in bioassay. The local strain of Beauveria bassiana (PSC-13) and Metarhizium anisopliae (PSC-11) was more virulent than t...
Pathogenecity of Metarhizium anisopliae on Helicoverpa armigera larvae instars
International Journal of Agricultural Invention, 2020
Studies on pathogenicity of M. anisopliae against I st-VI th instar H. armigera larvae revealed that larval mortality. The effect of Metarhizium anisopliae spore/ml against Helicoverpa armigera larval instars was significantly higher recorded showed that in the results revealed that all the treatments were significantly larval mortality. The results revealed that all the treatments were significantly higher effective in larval mortality as compared to other larval instars. The data recorded on 4, 6, 8 11 and 14 day after pathogencity of various larval instars in the I st instar of H. armigera with 1.8 x 10 9 spores suspension, was the best I st instars larva H. armigera per cent mortality by M. anisopliae up to (35.63) followed by 73.39 (85.69) (98.37) and (100.0) production was significantly recorded.
International Journal of Tropical Insect Science, 2015
The aim of this study was to identify and develop entomopathogenic fungi as biopesticides for management of Maruca vitrata (Fabricius). Fourteen isolates of Metarhizium anisopliae (Metchnikoff) Sorokin and six of Beauveria bassiana (Bals.-Criv.) Vuill. were screened against first instar larvae of M. vitrata. The two most virulent isolates were selected and further tested for production in four liquid media. Different formulations of one isolate were evaluated against different developmental stages. Metarhizium anisopliae ICIPE 18 and ICIPE 69 caused highest larval mortality of 91 and 81%, with lethal time to 50% mortality (LT 50) values of 1.8 and 1.7 days and LC 50 of 1.07 £ 10 7 and 3.01 £ 10 6 conidia/ml, respectively. ICIPE 69 yielded more biomass and propagules in two liquid media than ICIPE 18. All developmental stages and adult moths were susceptible to fungal infection and horizontal transmission caused a significant reduction in fecundity. Isolate ICIPE 69 was identified as the most potent isolate for managing M. vitrata based on demonstrated efficacy against different developmental stages and amenability to production in liquid media and could be utilized as an alternative to pesticides in cowpea IPM.
2009
Integrated Pest Management (IPM) involves the use of cultural, chemical and biological agents and more recently genetic modification to limit pest incidence in crop production. The effectiveness of the biological agents is dependent on the compatibility of the living organisms with the cultural and chemical components as well as other living organisms used in the programme. In this paper the pathogenicity of four isolates (ARSEF 932, ARSEF 954, IMI 152222 and IMI 299982) of the entomopathogenic fungus, Metarhizium anisopliae was tested against selected natural enemies viz., Cryptolaemus montrouzieri, Anagyrus kamali, Lysiphlebus testaceipes and Bracon thurberiphagae. Bioassays and probit analyses were used to determine the LC 50 and LT 50 of each fungal isolates against the natural enemies. The results of this study will be used to assist in the determination of the compatibility of M. anisopliae with the selected natural enemies when developing IPM programs in which these natural e...
Pathogencity of two entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae isolates was evaluated against sugar beet fly, Pegomyia mixta, beet moth, Scrobipalpa ocellatella and cowpea aphid, Aphis craccevora under laboratory conditions. The obtained results showed that the third instar larvae of P. mixta and S. ocellatella were affected by both isolates than the pupae after the tenth day from treatment. Mortality was occurring in larvae after the third day of treatment, while it occurs in pupae after the fourth day. A. craccevora slightly affected by both isolates with all concentrations. The maximum percent of mortality was 32.6% with the third concentration (2 x 10 5 conidia /ml) of M. anisopliae isolate. M. anisopliae isolate was more effective on three pests than B. bassiana isolates. These results suggested that both B. bassiana and M. anisopliae isolates were virulent against the larvae and pupae of P. mixta and S. ocellatella but slight virulent on A. craccevora.