Beauveria bassiana efficiency to Hedypathes betulinus control in yerba maté, Ilex paraguariensis

O controle das pragas da erva-mate, dentre as quais a broca-da-erva-mate, Hedypathes betulinus, é limitado principalmente a técnicas silviculturais e catação manual, pois não é permitida a aplicação de agroquímicos nessa cultura. A fim de contribuir com informações para o controle biológico de H. betulinus, o presente trabalho teve por objetivos determinar a eficácia e o número de aplicações anuais do micoinseticida à base do fungo entomopatogênico Beauveria bassiana para o controle dessa praga. Os experimentos foram conduzidos em uma área de erva-mate em monocultura, no município de Campo Alegre, SC, Brasil. O formulado foi pulverizado no tronco e na base das árvores, de acordo com um cronograma de duas ou três aplicações, em diferentes meses do ano. Constatou-se a eficácia com a utilização do formulado, sendo que os dados de captura das áreas tratadas diferiram estatisticamente da testemunha e do tratamento com catação manual. Contudo, não houve diferença estatística entre os tratamentos com duas e três aplicações, sendo capturados, respectivamente, 18,4% e 17,7% dos insetos marcados. Assim, apenas duas pulverizações com B. bassiana realizadas nos meses de novembro e fevereiro são eficientes para o controle de H. betulinus e manutenção do inóculo na área de erva-mate em monocultura.Palavras chave: Fungo entomopatogênico; controle biológico; flutuação populacional.AbstractBeauveria bassiana efficiency to Hedypathes betulinus control in yerba maté, Ilex paraguariensis. Yerba mate pest control, especially Hedypathes betulinus, is limited basically to silvicultural practices and insect removal, once application of chemical insecticides in such crop is not allowed. This research aimed to produce data for biological control of H. betulinus by evaluation of efficiency and number of applications of an entomopathogenic fungus Beauveria bassiana formulation for control of such pest species. The experiment was carried out on a yerba maté monoculture area, in Campo Alegre county, Santa Catarina, Brazil. The fungus was sprayed on trees’ trunk, following a chronogram of two and three applications, in different months. Efficiency of B. bassiana formulation could be demonstrated by the number of recaptured insects in areas of application, which was statistically lower than the one in the control area. However, there was no significant difference between two and three fungus application, with, respectively 18.4% and 17.7% of recaptured insects. Thus, only two yearly B. bassiana applications, in November and February, are enough to control H. betulinus and keep inoculum in an area of yerba maté monoculture. Keywords: Entomopathogenic fungi; biological control; insect fluctuation. Yerba mate pest control, especially Hedypathes betulinus, is limited basically to silvicultural practices and insect removal, once application of chemical insecticides in such crop is not allowed. This research aimed to produce data for biological control of H. betulinus by evaluation of efficiency and number of applications of an entomopathogenic fungus Beauveria bassiana formulation for control of such pest species. The experiment was carried out on a yerba maté monoculture area, in Campo Alegre county, Santa Catarina, Brazil. The fungus was sprayed on trees’ trunk, following a chronogram of two and three applications, in different months. Efficiency of B. bassiana formulation could be demonstrated by the number of recaptured insects in areas of application, which was statistically lower than the one in the control area. However, there was no significant difference between two and three fungus application, with, respectively 18.4% and 17.7% of recaptured insects. Thus, only two yearly B. bassiana applications, in November and February, are enough to control H. betulinus and keep inoculum in an area of yerba maté monoculture

Persistence in soil of inoculum of Beauveria bassiana used to control Hedypathes betulinus in yerba maté plantation, Ilex paraguariensis

O controle da broca-da-erva-mate, Hedypathes betulinus, limita-se ao emprego de práticas silviculturais e catação manual dos insetos adultos, não sendo permitido o uso de inseticidas químicos na cultura. Esta pesquisa teve por objetivos verificar a presença natural de Beauveria bassiana no solo de plantio em monocultura de erva-mate, determinar a persistência de B. bassiana no solo após duas e três aplicações do fungo e averiguar a influência de fatores abióticos na estabilidade do fungo no solo. O estudo foi conduzido em um erval no município de Campo Alegre, Santa Catarina, Brasil, onde foram coletadas amostras de solo em duas áreas, para avaliação da presença natural de inóculos do fungo B. bassiana, procedendo-se à contagem, isolamento e identificação.Não foi detectada a ocorrência natural do fungo no solo em nenhuma das duas áreas. Após essa confirmação, foram realizadas pulverizações com B. bassiana em ambas as áreas, sendo que em uma ocorreram duas e na outra três aplicações. Após a última pulverização, realizada em fevereiro/2006, verificou-se que os inóculos do fungo persistiram por 90 dias na área com duas aplicações e 120 dias na área com três aplicações. A temperatura afetou a persistência do fungo no solo em ambas as áreas, mas a umidade relativa não mostrou influência sobre os inóculos em campo.Palavras-chave: Broca-da-erva-mate; controle biológico; epizootia; fungo entomopatogênico. AbstractPersistence in soil of inoculum of Beauveria bassiana used to control Hedypathes betulinus in yerba maté plantation, Ilex paraguariensis. Control measures of Hedypathes betulinus are restricted to agricultural practices and hand picking of adult insects. No chemical control is allowed in yerba maté cultivation areas. The objectives of this research were to verify the natural occurrence of the entomopathogenic fungus Beauveria bassiana in the soil of yerba maté in monoculture; to determine the persistence of inoculums in the soil after applications of the fungus; and to evaluate the influence of abiotic factors on fungus stability in the soil. The soil samples were taken from two experimental areas in a yerba maté plantation in the county of Campo Alegre, Santa Catarina, Brazil. The samples were analyzed in order to count, isolate and identify inoculums of B. bassiana and other fungi. After the confirmation that B. bassiana was not present in the soil, a suspension of the fungus was applied, twice in one of the areas and three times in the other. After the last application in February/2006, the inoculum persisted for 90 and 120 days, in the area with two and three applications, respectively. The temperature affected the persistence of B. bassiana in soil; however, the relative humidity did not.Keywords: Biological control; epizooty; entomopathogenic fungus; wood borer. Control measures of Hedypathes betulinus are restricted to agricultural practices and hand picking of adult insects. No chemical control is allowed in yerba maté cultivation areas. The objectives of this research were to verify the natural occurrence of the entomopathogenic fungus Beauveria bassiana in the soil of yerba maté in monoculture; to determine the persistence of inoculums in the soil after applications of the fungus; and to evaluate the influence of abiotic factors on fungus stability in the soil. The soil samples were taken from two experimental areas in a yerba maté plantation in the county of Campo Alegre, Santa Catarina, Brazil. The samples were analyzed in order to count, isolate and identify inoculums of B. bassiana and other fungi. After the confirmation that B. bassiana was not present in the soil, a suspension of the fungus was applied, twice in one of the areas and three times in the other. After the last application in February/2006, the inoculum persisted for 90 and 120 days, in the area with two and three applications, respectively. The temperature affected the persistence of B. bassiana in soil; however, the relative humidity did not