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Mohamed Ezz El-din Mostafa - One of the best experts on this subject based on the ideXlab platform.
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Patogenicidade de duas variedades de Bacillus thuringiensis Berliner para lavras de lepidoptera e diptera
[s.n.], 2021Co-Authors: Mohamed Ezz El-din MostafaAbstract:Acompanha memorialTese (livre-docencia) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: A patogenicidade de duas variedades de Bacillus tnuringiensis Berliner foi investigada em larvas de Lepi-doptera e Diptera. Através do enfoque patológico no estudo, tentou-se esclarecer alguns aspectos importantes nas áreas de pesquisa, industrialização de patógenos e aplicação de produtos à base de B. thuringiensis no campo. Os sintomas externos pré-mortais foram descritos em larvas de Lepidoptera infectadas por B. thuringiensis var. kurstaki e em larvas de Diptera infectadas por B. thuringien-sis var. israelensis. Algumas alterações histológicas foram detectadas em alguns tecidos de tais larvas, principalmente , no intestino médio, sistema nervoso e musculatura. As alterações observadas nesses tecidos foram relacionadas com o desencadeamento dos sintomas externos da bacteriose. A variedade kurstaki teve ação fatal lenta (2 a 3 dias) nas larvas de Lepidoptera, quando comparada com a ação da variedade israelensis nas larvas aquáticas de Diptera,onde a morte ocorre em poucas horas após a infecção. Nenhum dos lepidópteros estudados pertence o tipo I da classicificação de Heimpel & Angus (1959); pois não ocorreu paralisia geral ou aumento no pH da hemolinfa nas larvas doentes. Entre as larvas dessas espécies, as de Brasso-lis sophorae revelaram-se mais susceptiveis em relação às demais. Por outro lado, as larvas de Spodoptera latifascia e-ram as mais resistentes à mesma variedade kurstaki ( sorotipo H-3a:3b). A origem do patógeno, o hospedeiro do qual este foi isolado e o processamento da produção comercial, além da variedade do bacilo e da espécie do inseto infectado, eram fatores responsáveis pela variação nas respostas das larvas infectadas. A expressão da quantidade do patógeno em termos de Unidades Internacionais de virulência / unidade de peso do inseto tratado revelou-se altamente precisa para comparações de susceptibilidade de insetos e virulência de produtos. 0 uso de critérios de DL50 e CL50 _ mostrou-se muito adequado, e até pode ser recomendado, para estudos com populações de insetos geneticamente menos variáveis. A resposta dos indivíduos, no caso, seria diretamente relacionada com e em função da dose ou a concentração aplicada. 0 uso de TL50 , por outro lado, revelou-se mais funcional e, também, pode ser recomendado para investigações com populações de maior variabilidade genética. Os níveis de susceptibilidade revelados para cada uma das espécies estudadas, indicaram a alta possibilidade de obter resultados satisfatórios no campo, quando produtos comerciais à base da variedade kurstaki forem aplicados contra larvas de B. sophorae , Alabama argillacea e Plodia inter-punctella em jardins e áreas urbanas, lavoura e armazéns respectivamente. A morte iniciou-se, nas larvas aquáticas dos dípteros estudados, apenas poucas horas após a infecção pela variedade israelensis. As larvas de Culex declarator (Culicidae) mostraram-se mais susceptíveis a essa variedade do que as lar vas de simulídeos, quando infectadas com este patógeno. Entre as duas espécies de simulídeos, as larvas de Simulium goeldii eram 4 vezes mais susceptíveis do que as de S. rorotaense. As larvas do último estádio de C. declarator revelaram-se mais susceptíveis ao patógeno do que as dos estádios iniciais. No mesmo tempo, as larvas no início do último estádio (42) eram mais susceptíveis do que no final do mesmo estádio. Este último aspecto, juntamente com a morte rápida causada pelo patógeno ( 2 a 3 horas), devem ser considerados nas recomendações de alguns órgãos oficiais no exterior. Tais órgãos, exigem que o 42 estádio larval de Aedes aegypti seja usado nos bioensaios de padronização de produtos à base da variedade israelensis ; porém, sem estabelecer uma fase desse estádio. A especificidade e a alta virulência da variedade israelensis para larvas aquáticas de Diptera, revelam o seu grande valor como agente promissor no controle microbiano de larvas de Culicidae e Simuliidae. Os sintomas externos observados nas larvas de. C. declarator, as alterações nistológicas e a morte rápida foram suficientemente convenientes para mostrar a ação da S-endo toxina produzida pelo patógeno. Tal toxina deve ter afetado drasticamente o sistema nervoso e a musculatura da larva, dificultando assim a manutenção desta na superfície da água e conseqüentemente a sua respiração do ar atmosférico. Assim , a larva afundada morreu por asfixia. Esses estudos revelaram a presença de um novo campo para investigações de patologia de insetos e controle microbiano para os dípteros aquáticos neotropicais e subtropicais . Tais investigações terão o seu alto valor do ponto de vista humano, desde que várias dessas espécies tem a sua importância como insetos vetores de doenças humanasAbstract: The pathogenicity of two varieties of Bacillus thuringiensis Berliner was investigated using some lepi-dopterous and dipterous larvae. The aim of the present study was to clarify certain aspects related to the application of Insect Pathology, such as susceptibility and virulence évalua tions, standardisation criteria, and field applications of microbial products to the control of some harmful Insects. The sequence of external symptoms was described in lepidopterous larvae infected with the B. thuringiensis var. kurstaki (syrotype K-3a:3b) and in dipterous larvae infected with the variety israelensis (syrotype H-14)-The histological alterations, in these infected larvae, were described, principally those in the mid-gut, nervous system, and musculature These alterations were found to be directly associated with the different external symptoms of the disease. The progress of the disease up to the death in the lepidopterous larvae lasted longer time (2-3 days) than in dipterous ones (2-3 hours). Type I of Heimpel & Angus (1959) classification did not occur among the lepidopterous species studied, since nei_ ther general paralysis nor pH alterations in the hemolymph were detected. Brassolis sophorae larvae were found to "be the most susceptible to syrotype H-3a:3b, when compared with the other lepidopterous species. On the other hand, Spodoptera lati-fascia larvae were the most resistant. Origin, natural host, and mass production criteria of the pathogen, in addition to its variety and the tested Insect species, were the most important factors responsible for the variation in responses of the infected larvae. Therefore, these aspects should be considered to choice the more adequate product for each Insect species to be combatted. The quantity of the pathogen expressed in International Units of toxicity per unit of body weight, showed to be highly precise for the comparison of Insect susceptibility and pathogen virulence. The LD^Q and LC^0 criteria were found to be suitable and, therefore, can be recommended for investigations where the populations of Insects are of low genetic variability. On the other hand, for genetically variable populations, the LT^q was found to be more adequate. B. sophorae, Alabama argillacea and Flodia inter-punctella were found to be highly susceptible to the syrotype H-3a:3b. Therefore, this pathogen can be recommended for their control. The aquatic dipteran larvae, studied in the present work, died some hours after infection with syrotype H-14.Culex declarator (Culicidae) larvae were more susceptible than those .132 . of the simulid species. Within Simuliidae, Simulium goeldii larvae were 4 times more susceptible than the S_. rorotaense ones. The last instar (4th.) larvae of C. declarator were more susceptible than those of the first instars. Moreover, within the same instar, these larvae showed different levels of susceptibility. In the initial phase of the last instar they were more susceptible than in the final phase. These informations, in addition to the rapid fatal action of the toxin in dipteran aquatic larvae, should be considered by the governamental agencies, in establishing standardization criteria for future commercial products based on this variety.At the present, these agencies establish the 4th instar larvae of Aedes aegypti as a test Insect for stadardization bio-assays, ignoring the difference in susceptibility within the same instar. Because of the high specificity and virulence of B. thuringiensis var. israelensis for dipteran aquatic larvae, it can be considered as a promissing agent for microbial control of mosquitos and black flies larvae. Considering the mode of action of syrotype H-14 in mosquito larvae, the results led us to beleive that the £-endotoxin liberated in the high alkaline mid-gut affected the ventral nervous system and consequently the musculature , provoking disfunction of the latter.The effect on the muscles made the larva lose its capacity to maintain itself at the water surface. Consequently, the larva submerged and died by asphixiation. The observed sequence of the external symptoms, as well as the histological alterations sustained this hypothesis. The results obtained in the present study reveal the possibility to utilize the syrotype H-14 in the control of vectors of some human diseases, such as malaria and filaria This application, however, requires additional extensive research work to complete urgently needed informationsLivre DocênciaLivre-Docente em Ciencias Biologica
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Patogenicidade de duas variedades de Bacillus thuringiensis Berliner para lavras de lepidoptera e diptera
[s.n.], 2018Co-Authors: Mohamed Ezz El-din MostafaAbstract:Acompanha memorialTese (livre-docencia) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: A patogenicidade de duas variedades de Bacillus tnuringiensis Berliner foi investigada em larvas de Lepi-doptera e Diptera. Através do enfoque patológico no estudo, tentou-se esclarecer alguns aspectos importantes nas áreas de pesquisa, industrialização de patógenos e aplicação de produtos à base de B. thuringiensis no campo. Os sintomas externos pré-mortais foram descritos em larvas de Lepidoptera infectadas por B. thuringiensis var. kurstaki e em larvas de Diptera infectadas por B. thuringien-sis var. israelensis. Algumas alterações histológicas foram detectadas em alguns tecidos de tais larvas, principalmente , no intestino médio, sistema nervoso e musculatura. As alterações observadas nesses tecidos foram relacionadas com o desencadeamento dos sintomas externos da bacteriose. A variedade kurstaki teve ação fatal lenta (2 a 3 dias) nas larvas de Lepidoptera, quando comparada com a ação da variedade israelensis nas larvas aquáticas de Diptera,onde a morte ocorre em poucas horas após a infecção. Nenhum dos lepidópteros estudados pertence o tipo I da classicificação de Heimpel & Angus (1959); pois não ocorreu paralisia geral ou aumento no pH da hemolinfa nas larvas doentes. Entre as larvas dessas espécies, as de Brasso-lis sophorae revelaram-se mais susceptiveis em relação às demais. Por outro lado, as larvas de Spodoptera latifascia e-ram as mais resistentes à mesma variedade kurstaki ( sorotipo H-3a:3b). A origem do patógeno, o hospedeiro do qual este foi isolado e o processamento da produção comercial, além da variedade do bacilo e da espécie do inseto infectado, eram fatores responsáveis pela variação nas respostas das larvas infectadas. A expressão da quantidade do patógeno em termos de Unidades Internacionais de virulência / unidade de peso do inseto tratado revelou-se altamente precisa para comparações de susceptibilidade de insetos e virulência de produtos. 0 uso de critérios de DL50 e CL50 _ mostrou-se muito adequado, e até pode ser recomendado, para estudos com populações de insetos geneticamente menos variáveis. A resposta dos indivíduos, no caso, seria diretamente relacionada com e em função da dose ou a concentração aplicada. 0 uso de TL50 , por outro lado, revelou-se mais funcional e, também, pode ser recomendado para investigações com populações de maior variabilidade genética. Os níveis de susceptibilidade revelados para cada uma das espécies estudadas, indicaram a alta possibilidade de obter resultados satisfatórios no campo, quando produtos comerciais à base da variedade kurstaki forem aplicados contra larvas de B. sophorae , Alabama argillacea e Plodia inter-punctella em jardins e áreas urbanas, lavoura e armazéns respectivamente. A morte iniciou-se, nas larvas aquáticas dos dípteros estudados, apenas poucas horas após a infecção pela variedade israelensis. As larvas de Culex declarator (Culicidae) mostraram-se mais susceptíveis a essa variedade do que as lar vas de simulídeos, quando infectadas com este patógeno. Entre as duas espécies de simulídeos, as larvas de Simulium goeldii eram 4 vezes mais susceptíveis do que as de S. rorotaense. As larvas do último estádio de C. declarator revelaram-se mais susceptíveis ao patógeno do que as dos estádios iniciais. No mesmo tempo, as larvas no início do último estádio (42) eram mais susceptíveis do que no final do mesmo estádio. Este último aspecto, juntamente com a morte rápida causada pelo patógeno ( 2 a 3 horas), devem ser considerados nas recomendações de alguns órgãos oficiais no exterior. Tais órgãos, exigem que o 42 estádio larval de Aedes aegypti seja usado nos bioensaios de padronização de produtos à base da variedade israelensis ; porém, sem estabelecer uma fase desse estádio. A especificidade e a alta virulência da variedade israelensis para larvas aquáticas de Diptera, revelam o seu grande valor como agente promissor no controle microbiano de larvas de Culicidae e Simuliidae. Os sintomas externos observados nas larvas de. C. declarator, as alterações nistológicas e a morte rápida foram suficientemente convenientes para mostrar a ação da S-endo toxina produzida pelo patógeno. Tal toxina deve ter afetado drasticamente o sistema nervoso e a musculatura da larva, dificultando assim a manutenção desta na superfície da água e conseqüentemente a sua respiração do ar atmosférico. Assim , a larva afundada morreu por asfixia. Esses estudos revelaram a presença de um novo campo para investigações de patologia de insetos e controle microbiano para os dípteros aquáticos neotropicais e subtropicais . Tais investigações terão o seu alto valor do ponto de vista humano, desde que várias dessas espécies tem a sua importância como insetos vetores de doenças humanasAbstract: The pathogenicity of two varieties of Bacillus thuringiensis Berliner was investigated using some lepi-dopterous and dipterous larvae. The aim of the present study was to clarify certain aspects related to the application of Insect Pathology, such as susceptibility and virulence évalua tions, standardisation criteria, and field applications of microbial products to the control of some harmful Insects. The sequence of external symptoms was described in lepidopterous larvae infected with the B. thuringiensis var. kurstaki (syrotype K-3a:3b) and in dipterous larvae infected with the variety israelensis (syrotype H-14)-The histological alterations, in these infected larvae, were described, principally those in the mid-gut, nervous system, and musculature These alterations were found to be directly associated with the different external symptoms of the disease. The progress of the disease up to the death in the lepidopterous larvae lasted longer time (2-3 days) than in dipterous ones (2-3 hours). Type I of Heimpel & Angus (1959) classification did not occur among the lepidopterous species studied, since nei_ ther general paralysis nor pH alterations in the hemolymph were detected. Brassolis sophorae larvae were found to "be the most susceptible to syrotype H-3a:3b, when compared with the other lepidopterous species. On the other hand, Spodoptera lati-fascia larvae were the most resistant. Origin, natural host, and mass production criteria of the pathogen, in addition to its variety and the tested Insect species, were the most important factors responsible for the variation in responses of the infected larvae. Therefore, these aspects should be considered to choice the more adequate product for each Insect species to be combatted. The quantity of the pathogen expressed in International Units of toxicity per unit of body weight, showed to be highly precise for the comparison of Insect susceptibility and pathogen virulence. The LD^Q and LC^0 criteria were found to be suitable and, therefore, can be recommended for investigations where the populations of Insects are of low genetic variability. On the other hand, for genetically variable populations, the LT^q was found to be more adequate. B. sophorae, Alabama argillacea and Flodia inter-punctella were found to be highly susceptible to the syrotype H-3a:3b. Therefore, this pathogen can be recommended for their control. The aquatic dipteran larvae, studied in the present work, died some hours after infection with syrotype H-14.Culex declarator (Culicidae) larvae were more susceptible than those .132 . of the simulid species. Within Simuliidae, Simulium goeldii larvae were 4 times more susceptible than the S_. rorotaense ones. The last instar (4th.) larvae of C. declarator were more susceptible than those of the first instars. Moreover, within the same instar, these larvae showed different levels of susceptibility. In the initial phase of the last instar they were more susceptible than in the final phase. These informations, in addition to the rapid fatal action of the toxin in dipteran aquatic larvae, should be considered by the governamental agencies, in establishing standardization criteria for future commercial products based on this variety.At the present, these agencies establish the 4th instar larvae of Aedes aegypti as a test Insect for stadardization bio-assays, ignoring the difference in susceptibility within the same instar. Because of the high specificity and virulence of B. thuringiensis var. israelensis for dipteran aquatic larvae, it can be considered as a promissing agent for microbial control of mosquitos and black flies larvae. Considering the mode of action of syrotype H-14 in mosquito larvae, the results led us to beleive that the £-endotoxin liberated in the high alkaline mid-gut affected the ventral nervous system and consequently the musculature , provoking disfunction of the latter.The effect on the muscles made the larva lose its capacity to maintain itself at the water surface. Consequently, the larva submerged and died by asphixiation. The observed sequence of the external symptoms, as well as the histological alterations sustained this hypothesis. The results obtained in the present study reveal the possibility to utilize the syrotype H-14 in the control of vectors of some human diseases, such as malaria and filaria This application, however, requires additional extensive research work to complete urgently needed informationsTese (livre-docencia) - UniverLivre-Docente em Ciencias Biologica
Anwar Ruly - One of the best experts on this subject based on the ideXlab platform.
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PENGGUNAAN CENDAWAN ENTOMOPATOGEN Beauveria bassiana (BALSAMO) VUILLEMIN DAN Lecanicillium lecanii (ZIMM) ZARE & GAMS UNTUK MENGENDALIKAN Helopeltis antonii SIGN (HEMIPTERA: MIRIDAE) The Use of Entomopathogenic Fungi Beauveria bassiana (Balsamo)Vuill
'Institut Pertanian Bogor', 2018Co-Authors: Anggarawati, Sri Hastuti, Santoso Teguh, Anwar RulyAbstract:Helopeltis sp. has been known as one of major pests on tea, cacao and cashew plantation. Recently, genus Helopeltis is also reported attack Acacia plantation in Sumatra and Kalimantan. For such extensive plantation, low cost biocontrol agents like entomopathogenic fungi are choosen because of the simplicity for mass production. The objective of this study was to measure the effectiveness of Beauveria bassiana and Lecanicillium lecanii against Helopeltis sp. Both fungi that were used in this study were obtained from IPB Insect Pathology Laboratory. The tested Insect, Helopeltis sp. was collected from Gunung Mas tea plantation. The Insects were reared in laboratory. Four level of conidial density, 109, 108, 107, 106 conidia/ mL were applied to Helopeltis adult (B. bassiana) and 3rdinstar nymph (L. lecanii). Daily mortality was observed until seven days post treatment. The result showed that L. lecanii at 106 conidia/mL caused 96.25% mortality of 3rd instar nymph of Helopeltis sp. with the LC50 value at two days observation was 1.03 x 106 conidia/ mL, LT50 was 1.198 days and LT95 was 5.25 days. On the other hand, B. bassiana at 106 conidia/ mL caused 81.25%. mortality of adult Helopeltis sp. while 100% mortality could be attained by using 108 conidia/ mL. The LC50 of B. bassiana was 3.2 x 104 conidia/ mL, at four days observation and LT50 was 4.214 days. The two fungi were thus judged effective against Helopeltis sp. in this bio assay.Key words: Beauveria bassiana, conidia, density, Helopeltis sp., Lecanicillium lecanii, mortality
Ruly Anwar - One of the best experts on this subject based on the ideXlab platform.
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penggunaan cendawan entomopatogen beauveria bassiana balsamo vuillemin dan lecanicillium lecanii zimm zare gams untuk mengendalikan helopeltis antonii sign hemiptera miridae the use of entomopathogenic fungi beauveria bassiana balsamo vuillemin
Silvikultur Tropika - Journal of Tropical Silviculture Science and Technology, 2018Co-Authors: Sri Hastuti Anggarawati, Teguh Santoso, Ruly AnwarAbstract:Helopeltis sp. has been known as one of major pests on tea, cacao and cashew plantation. Recently, genus Helopeltis is also reported attack Acacia plantation in Sumatra and Kalimantan. For such extensive plantation, low cost biocontrol agents like entomopathogenic fungi are choosen because of the simplicity for mass production. The objective of this study was to measure the effectiveness of Beauveria bassiana and Lecanicillium lecanii against Helopeltis sp. Both fungi that were used in this study were obtained from IPB Insect Pathology Laboratory. The tested Insect, Helopeltis sp. was collected from Gunung Mas tea plantation. The Insects were reared in laboratory. Four level of conidial density, 109, 108, 107, 106 conidia/ mL were applied to Helopeltis adult (B. bassiana) and 3rdinstar nymph (L. lecanii). Daily mortality was observed until seven days post treatment. The result showed that L. lecanii at 106 conidia/mL caused 96.25% mortality of 3rd instar nymph of Helopeltis sp. with the LC50 value at two days observation was 1.03 x 106 conidia/ mL, LT50 was 1.198 days and LT95 was 5.25 days. On the other hand, B. bassiana at 106 conidia/ mL caused 81.25%. mortality of adult Helopeltis sp. while 100% mortality could be attained by using 108 conidia/ mL. The LC50 of B. bassiana was 3.2 x 104 conidia/ mL, at four days observation and LT50 was 4.214 days. The two fungi were thus judged effective against Helopeltis sp. in this bio assay.Key words: Beauveria bassiana, conidia, density, Helopeltis sp., Lecanicillium lecanii, mortality.
J Amritha N De Croos - One of the best experts on this subject based on the ideXlab platform.
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habitat association in two genetic groups of the Insect pathogenic fungus metarhizium anisopliae uncovering cryptic species
Applied and Environmental Microbiology, 2001Co-Authors: Michael J Bidochka, Andrena M Kamp, Michael T Lavender, Jason Dekoning, J Amritha N De CroosAbstract:Strains of Insect-pathogenic fungi with high virulence toward certain pest Insects have great potential for commercial biological control applications. Identifying such strains has been a central theme in using fungi for biological control. This theme is supported by a persistent paradigm in Insect Pathology which suggests that the host Insect is the predominant influence on the population genetics of Insect-pathogenic fungi. In this study, a population genetics analysis of the Insect-pathogenic fungus Metarhizium anisopliae from forested and agricultural habitats in Ontario, Canada, showed a nonrandom association of alleles between two distinct, reproductively isolated groups (index of multilocus association = 1.2). Analyses of the mitochondrial DNA showed no differences between the groups. The two groups were associated with different habitat types, and associations with Insect hosts were not found. The group from forested areas showed an ability for cold-active growth (i.e., 8°C), while the group from the agricultural area showed an ability for growth at high temperatures (i.e., 37°C) and resilience to UV exposure. These results represent a significant paradigm shift; habitat selection, not host Insect selection, drives the population structure of these Insect-pathogenic deuteromycetous fungi. With each group we observed recombining population structures as well as clonally reproducing lineages. We discuss whether these groups may represent cryptic species. Worldwide, M. anisopliae may be an assembly of cryptic species, each adapted to certain environmental conditions. The association of fungal genotypes with habitat but not with host Insects has implications on the criteria for utility of this, and perhaps other, fungal biocontrol agents.
Michael J Bidochka - One of the best experts on this subject based on the ideXlab platform.
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genetic groups of the Insect pathogenic fungus beauveria bassiana are associated with habitat and thermal growth preferences
Archives of Microbiology, 2002Co-Authors: Michael J Bidochka, Fiona V Menzies, Andrena M KampAbstract:A persistent paradigm in Insect Pathology is one that relates the Insect host to certain genetic groups of Insect-pathogenic fungi. This paradigm assumes that the genotype of an Insect-pathogenic fungus coevolves with a certain taxon of Insect host that it infects. The Insect-pathogenic fungus Beauveria bassiana shows a wide host range and is considered to be a facultative Insect pathogen. In this study, a population genetics analysis of B. bassiana from forested and agricultural habitats as well as from the Canadian Arctic showed distinct genetic groups associated with the three different habitats. Within each group, recombining population structures and clonally reproducing lineages were observed. The B. bassiana isolates were also assessed for their abilities to grow at 8, 15, 25 and 37 °C and for their tolerances to UV exposure. The genetic groups from the Arctic and from the forested habitats grew at lower temperatures, while the genetic group from the agricultural habitat grew at 37 °C and was tolerant to UV exposure. There were no clear associations between the genetic group and the ability to infect coleopteran or lepidopteran Insect larvae. There is increasing evidence that such studies represent a significant paradigm shift; habitat selection, not Insect host selection, drives the population structure of deuteromycetous Insect-pathogenic fungi. We suggest that adaptation to a certain habitat type is an important criterion for identifying Insect-pathogenic fungal strains for use in Insect biocontrol efforts.
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habitat association in two genetic groups of the Insect pathogenic fungus metarhizium anisopliae uncovering cryptic species
Applied and Environmental Microbiology, 2001Co-Authors: Michael J Bidochka, Andrena M Kamp, Michael T Lavender, Jason Dekoning, J Amritha N De CroosAbstract:Strains of Insect-pathogenic fungi with high virulence toward certain pest Insects have great potential for commercial biological control applications. Identifying such strains has been a central theme in using fungi for biological control. This theme is supported by a persistent paradigm in Insect Pathology which suggests that the host Insect is the predominant influence on the population genetics of Insect-pathogenic fungi. In this study, a population genetics analysis of the Insect-pathogenic fungus Metarhizium anisopliae from forested and agricultural habitats in Ontario, Canada, showed a nonrandom association of alleles between two distinct, reproductively isolated groups (index of multilocus association = 1.2). Analyses of the mitochondrial DNA showed no differences between the groups. The two groups were associated with different habitat types, and associations with Insect hosts were not found. The group from forested areas showed an ability for cold-active growth (i.e., 8°C), while the group from the agricultural area showed an ability for growth at high temperatures (i.e., 37°C) and resilience to UV exposure. These results represent a significant paradigm shift; habitat selection, not host Insect selection, drives the population structure of these Insect-pathogenic deuteromycetous fungi. With each group we observed recombining population structures as well as clonally reproducing lineages. We discuss whether these groups may represent cryptic species. Worldwide, M. anisopliae may be an assembly of cryptic species, each adapted to certain environmental conditions. The association of fungal genotypes with habitat but not with host Insects has implications on the criteria for utility of this, and perhaps other, fungal biocontrol agents.