RESUMO
Phytophthora infestans is the causal agent of late blight disease of potatoes and tomatoes. This disease causes devastating economic losses each year, and control is mainly achieved by the use of fungicides. Unfortunately, populations of P. infestans resistant to fungicides have been documented. Furthermore, studies have reported that sensitive isolates to the phenylamide fungicide, mefenoxam, become less sensitive in vitro after a single passage through sublethal concentrations of fungicide-amended medium. The first objective of this study was to investigate if isolates of P. infestans are capable of acquiring resistance to two additional systemic fungicides, fluopicolide (benzamide) and cymoxanil (cyanoacetamide-oxime). In contrast to the situation with mefenoxam, exposure of isolates to sublethal concentrations of fluopicolide and cymoxanil did not induce reduced sensitivity to these two fungicides. The second objective was to assess if reduced sensitivity to mefenoxam could occur in naturally sensitive isolates of other Phytophthora species and of Phytopythium sp., another oomycete plant pathogen. All Phytophthora spp. assessed (P. infestans, P. betacei, and P. pseudocryptogea) as well as Phytopythium sp. acquired resistance to mefenoxam after previous exposure through medium containing 1 µg ml-1 of mefenoxam. Interestingly, isolate 66 of Phytopythium sp. and the isolate of P. pseudocryptogea tested do not seem to be acquiring resistance to mefenoxam after exposure to medium containing 5 µg ml-1 of this fungicide. The tested isolates of P. palmivora and P. cinnamomi were extremely sensitive to mefenoxam, and thus it was not possible to perform a second transfer to access acquisition of resistance to this fungicide.
Assuntos
Alanina/análogos & derivados , Farmacorresistência Fúngica , Phytophthora infestans , Alanina/farmacologia , Fungicidas Industriais/farmacologia , Phytophthora infestans/efeitos dos fármacos , Solanum tuberosum/microbiologiaRESUMO
Resumen El objetivo de esta investigación es valorar el "Programa de desarrollo de habilidades de acompañamiento directivo" (PAD), analizando su influencia sobre (1) la percepción y satisfacción de los docentes y (2) la percepción de los directivos sobre su labor de acompañamiento y la satisfacción percibida en los docentes. Se aplicó un diseño cuasi-experimental. Participaron 12 directivos y 16 docentes de cuatro centros educativos de la Región del Bío-Bío, Chile. Se concluye que el PAD tiene un efecto de mejora en (1) la percepción y satisfacción de los docentes, y (2) en la percepción y satisfacción percibida por los directivos en los docentes, por los procesos de acompañamiento realizados. Las dimensiones del PAD que obtienen mayores puntuaciones son apoyo (en los docentes) y sistematicidad (en los directivos).
Abstract The main objective of this research is to validate "The board of directors accompaniment skills programme to teachers" (BAP), analysing its influence over (1) the perception and satisfaction among the teachers and (2) the perception the board of directors showed about their accompaniment work and the perceived satisfaction among the teachers. A quasi-experimental design was applied where twelve participants of four boards of directors coming from four schools of the 8th Region plus sixteen teachers participated. It is concluded that the BAP has an improvement effect over both the teachers' and the board of directors' perception and the satisfaction among the board of directors about the accompaniment process they perform. The dimensions that obtain major punctuations are a support (in the teachers) and systematicity (in the executives). The dimensions which get higher scores are support (given to the teachers) and organization (coming from the board of directors).