Patogenicidade de fungos entomopatogênicos e compatibilidade com inseticidas para o manejo de Diaphorina citri Kuwayama, (Hemiptera: Liviidae)
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Data
2016-05-30
Autores
Pinto, Ana Paula Ferreira [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Em 2004 foi relatada, nos pomares cítricos do estado de São Paulo, a presença do Huanglongbing. No Brasil, esta doença é causada pelas bactérias Candidatus Liberibacter asiaticus e Candidatus Liberibacter americanus, que são transmitidas pelo psílideo-dos-citros Diaphorina citri. A principal forma de controlar a doença é através do controle do inseto vetor, atualmente realizada com o uso de produtos fitossanitários. A mortalidade de adultos do psilídeo por fungos entomopatogênicos tem sido observada em campo, e alguns estudos estão sendo desenvolvidos, há pouca informação na literatura sobre o 2 efeito desses patógenos no controle microbiano do inseto vetor. Dessa forma, o presente estudo avaliou a patogenicidade de 20 isolados de fungos entomopatogênicos sobre adultos e ninfas de D. citri em condições de laboratório e semi-campo, bem como a sua compatibilidade com produtos fitossanitários, de diferentes grupos, utilizados na citricultura. Ninfas e adultos de D. citri, provenientes de criação em laboratório, foram expostas à uma concentração de 6,7x107 conídios/mL, avaliando a mortalidade desses insetos. Através dessa mortalidade foi determinado o tempo letal médio para 8 isolados, com maior porcentagem de mortalidade confirmada. A compatibilidade em laboratório foi observada adicionando os produtos químicos ao meio de cultura BDA, foi inoculado com o fungo em três pontos equidistantes da placa de Petri, a qual foi mantida em câmara climatizada tipo BOD por um período de sete dias. Após esse período, foram avaliados o crescimento vegetativo, esporulação, viabilidade do entomopatógeno. Em ensaios de laboratório, todos os produtos afetaram o desenvolvimento dos fungos e foi possível classificar os produtos como moderadamente tóxico, tóxico e compatível.
In 2004 it has been reported the presence of HLB, also known as "greening", in citrus orchards at São Paulo state. In Brazil, this disease is caused by bacteria Candidatus Liberibacter asiaticus and Candidatus Liberibacter americanus, which are transmitted by the psyllid-of-citrus Diaphorina citri. The main way to control the disease is through the control of the insect vector, which is currently carried out using chemicals. The mortality of psyllid adults by entomopathogenic fungi have been observed in the field and studies are being developed, but little is known about the effect of these pathogens in the insect vector control. Thus, we performed a study to determine the pathogenicity of entomopathogenic fungi on adults and nymphs of D. citri in laboratory and semi-field as well as its compatibility with pesticides used in citriculture. Laboratory created nymphs and adults of D. citri were exposed to a constant concentration of the pathogen 6,7x107 conidia/ml and it was observed the mortality of these insects. Through this mortality it was determined the median lethal time for 8 isolates, confirmed with the best mortality percentage. Laboratory compatibility was observed by incorporating chemicals to PDA culture medium which, after solidification, were inoculated with the fungus at three equidistant points of the Petri dish, which was kept in BOD chamber for a period of seven days. After this period, its vegetative growth, sporulation, viability of the pathogen has been evaluated. It has been observed in laboratory that all products affected the development of the fungi and it was possible to classify products as moderately toxic, toxic and compatible.
In 2004 it has been reported the presence of HLB, also known as "greening", in citrus orchards at São Paulo state. In Brazil, this disease is caused by bacteria Candidatus Liberibacter asiaticus and Candidatus Liberibacter americanus, which are transmitted by the psyllid-of-citrus Diaphorina citri. The main way to control the disease is through the control of the insect vector, which is currently carried out using chemicals. The mortality of psyllid adults by entomopathogenic fungi have been observed in the field and studies are being developed, but little is known about the effect of these pathogens in the insect vector control. Thus, we performed a study to determine the pathogenicity of entomopathogenic fungi on adults and nymphs of D. citri in laboratory and semi-field as well as its compatibility with pesticides used in citriculture. Laboratory created nymphs and adults of D. citri were exposed to a constant concentration of the pathogen 6,7x107 conidia/ml and it was observed the mortality of these insects. Through this mortality it was determined the median lethal time for 8 isolates, confirmed with the best mortality percentage. Laboratory compatibility was observed by incorporating chemicals to PDA culture medium which, after solidification, were inoculated with the fungus at three equidistant points of the Petri dish, which was kept in BOD chamber for a period of seven days. After this period, its vegetative growth, sporulation, viability of the pathogen has been evaluated. It has been observed in laboratory that all products affected the development of the fungi and it was possible to classify products as moderately toxic, toxic and compatible.
Descrição
Palavras-chave
Huanglongbing, Greening, Controle microbiano, Fungos entomopatogênicos, Psilídeo-dos-citros, Microbial control, Entomopathogenic fungi, Citruspsyllid