ABSTRACT
Pandora neoaphidis overwintering had been investigated by monitoring its prevalence in Myzus persicae populations in open fields. Cabbage plants in field plots were weekly taken after mycosis initiation, to count and examine the living and dead aphids infected by P. neoaphidis. Based on the field data, infection levels (I) varied with field temperature (T), relative humidity (RH) and aphid count (numbers of living aphids per plant, N) over days (D), fitting well to the modified logistic equation I=0.91/[1+exp(8.5+(2.0H T H RH-20.2NI0)D)] (r²=0.897), where H T indicated daily hours of low temperature (<4°C), H RH daily hours of high air humidity (>90% RH) and I0 primary infection level. The model demonstrated the abiotic and biotic factors influencing P. neoaphidis mycosis development in winter, and also verifies the fungal overwintering by infecting available host aphids without a resting stage. Ultimately, P. neoaphidis mycosis reduced 81.4% of aphid populations, presenting great potential for biocontrol.
Subject(s)
Abiotic Factors , Aphids/pathogenicity , Environmental Monitoring , Fungi , Hibernation , Models, Anatomic , Mycoses , Vegetables , Brassica , Environmental Microbiology , Food Samples , Methods , Prevalence , MethodsABSTRACT
Three species of Entomophthorales entomopathogenic fungi (Zygomycotina: Zygomycetes) have been identified from insects in agricultural crops (Buenos Aires Province, Argentina): Zoophthora radicans Batko (Brefeld); Entomophthora planchoniana Cornu and Pandora gammae (Weiser) Humber. Fungal structure measurements are reported.
Se informa de tres especies de hongos Entomophthorales en insectos encontrados en cultivos agrícolas en la Provincia de Buenos Aires, Argentina: Zoophthora radicans Batko (Brefeld); Entomophthora planchoniana Cornu y Pandora gammae (Weiser) Humber. Se incluyen las medidas de las estructuras fúngicas.
Subject(s)
Animals , Entomophthorales/pathogenicity , Insecta/microbiology , Host-Pathogen Interactions , Crops, Agricultural/microbiology , Zygomycosis/microbiology , Argentina , Population Density , Entomophthorales/classification , Entomophthorales/isolation & purification , Species SpecificityABSTRACT
Relata-se o resultado de um inventário de patógenos de ácaros plantícolas e edáficos realizado através de um estudo da diversidade de ácaros de importância agrícola, principalmente no estado de São Paulo. Várias espécies de Eriophyoidea foram encontradas infectadas por espécies do fungo Hirsutella sp. Esporos de resistência de fungos Entomophthorales foram observados em ácaros das seguintes famílias: Ascidae, Phytoseiidae, Stigmaeidae, Tetranychidae e Tydeidae. Uma infecção do eriofiídeo Retracus johnstoni Keifer, associado à palmeira Syagrus romanzoffiana (Cham.) Glassman,por Cladosporium sp., também foi observada. Este fungo foi isolado e cultivado em meio artificial. Possíveis usos dos patógenos encontrados para fins de controle biológico são discutidos.
During a study on the diversity of mites of agricultural importance, we made an inventory of pathogens infecting plant inhabiting and edaphic mites, mainly in the State of São Paulo, Brazil. Several species of Eriophyoidea were found to be infected by Hirsutella sp. Resting spores of Entomophthorales were observed in mites of the following families: Ascidae, Phytoseiidae, Stigmaeidae, Tetranychidae and Tydeidae. A Cladosporium sp. infection was noted in the eriophyid Retracus johnstoni Keifer, a pest of the palm tree Syagrus romanzoffiana (Cham.) Glassman. The fungus was isolated and cultured in artificial medium. The possible use of the observed pathogens for microbial control purposes is discussed.