Análise de risco da ocorrência de Sigatoka-negra baseada em modelos polinomiais: um estudo de caso

Abstract

RESUMOA Sigatoka-negra (Mycosphaerella fijiensis) ameaça os bananais comerciais em todas as áreas produtoras do mundo e provoca danos quantitativos e qualitativos na produção, acarretando sérios prejuízos financeiros. Faz-se necessário o estudo da vulnerabilidade das plantas em diversos estádios de desenvolvimento e das condições climáticas favoráveis à ocorrência da doença. Objetivou-se com este trabalho desenvolver um modelo probabilístico baseado em funções polinomiais que represente o risco de ocorrência da Sigatokanegra em função da vulnerabilidade decorrente de fatores intrínsecos à planta e ao ambiente. Realizou-se um estudo de caso, em bananal comercial localizado em Jacupiranga, Vale do Ribeira, SP, considerando o monitoramento semanal do estado da evolução da doença, séries temporais de dados meteorológicos e dados de sensoriamento remoto. Foram gerados mapas georreferenciados do risco da Sigatoka-negra em diferentes épocas do ano. Um modelo para estimar a evolução da doença a partir de imagens de satélite foi obtido com coeficiente de determinação R 2 igual a 0,9. A metodologia foi desenvolvida para a detecção de épocas e locais que reúnem condições favoráveis à ocorrência da Sigatoka-negra e pode ser aplicada, com os devidos ajustes, em diferentes localidades, para avaliar o risco da ocorrência da doença em polos produtores de banana. Palavras-chave: Mychosphaerella fijiensis, modelagem, previsão. ABSTRACT Risk analysis of Black Sigatoka occurrence based on polynomial models: A case studyBlack Sigatoka (Mycosphaerella fijiensis) threatens the banana trade in most of world's producing areas, damaging the production and bringing significant financial loss. It is necessary to study the plant's susceptibility in the various developmental stages and climatic conditions that favor the disease occurrence. This paper presents a probabilistic model based on polynomial functions for estimating the risk of Black Sigatoka occurrence. A case study was developed in a commercial banana plantation located in Jacupiranga, Vale do Ribeira, SP, Brazil, considering the weekly monitoring of the disease's state evolution (EE), time series of meteorological data and remote sensing data. Georeferenced risk maps were prepared for different dates. We obtained a model to estimate the evolution of the disease from satellite imagery, with a coefficient of determination of 0.9. This methodology was developed for the detection of times and locations that have favorable conditions to the occurrence of Black Sigatoka and can be applied, with appropriate adjustments for different locations, to assess the risk of disease occurrence in other areas of banana production.

Evidence of Resistance to QoI Fungicides in Contemporary Populations of Mycosphaerella fijiensis, M. musicola and M. thailandica from Banana Plantations in Southeastern Brazil

“…Subsequently, the pieces of filter paper colonized by the fungus mycelium were transferred to cryotubes with silica gel for cryo-preservation at −20 °C. In SPVR-I, the management was based on intensive fungicide sprays, with around 8 to 14 fungicide calendar-based applications per year to control black Sigatoka, mostly because of the extremely predisponent weather conditions for the disease, which includes high humidity (>90%), the presence of leaf wetness and temperatures ranging from 26-28 • C [2,19,[32][33][34]. The Vale do Ribeira region represents the highest banana production both in São Paulo State and Brazil, where the susceptible banana varieties Prata and Nanica predominate [7,19,33].…”

“…In SPVR-I, the management was based on intensive fungicide sprays, with around 8 to 14 fungicide calendar-based applications per year to control black Sigatoka, mostly because of the extremely predisponent weather conditions for the disease, which includes high humidity (>90%), the presence of leaf wetness and temperatures ranging from 26-28 • C [2,19,[32][33][34]. The Vale do Ribeira region represents the highest banana production both in São Paulo State and Brazil, where the susceptible banana varieties Prata and Nanica predominate [7,19,33]. In plantations from these susceptible banana varieties under the predominant highly favorable weather conditions in the Vale do Ribeira, the pathogens' incubation period could range from as low as 13 to 14 days, whereas under unfavorable weather the incubation period could be extended up to 35 days [7,19,33,34].…”

“…The Vale do Ribeira region represents the highest banana production both in São Paulo State and Brazil, where the susceptible banana varieties Prata and Nanica predominate [7,19,33]. In plantations from these susceptible banana varieties under the predominant highly favorable weather conditions in the Vale do Ribeira, the pathogens' incubation period could range from as low as 13 to 14 days, whereas under unfavorable weather the incubation period could be extended up to 35 days [7,19,33,34]. Intensive fungicides sprays are usually scheduled to coincide with the continuous emergence of new banana leaves, which are highly susceptible to infection [7].…”

Resistance to Site-Specific Succinate Dehydrogenase Inhibitor Fungicides Is Pervasive in Populations of Black and Yellow Sigatoka Pathogens in Banana Plantations from Southeastern Brazil

“…The geographical distribution and prevalence of the SDC in Brazil follow a humidity cline. For instance, black Sigatoka is considered more prevalent and destructive under conducive weather conditions, which include high humidity (>90%), the presence of leaf wetness, and temperatures ranging from 26-28 • C [8, [14][15][16][17]. In banana plantations where the susceptible and widely cultivated varieties Prata and Nanica [6,18] are used, the incubation period for Mf could be as short as 13 to 14 days, whereas under unfavorable conditions, the pathogen's incubation period could extend to 35 days [4,14,[16][17][18].…”

“…For instance, black Sigatoka is considered more prevalent and destructive under conducive weather conditions, which include high humidity (>90%), the presence of leaf wetness, and temperatures ranging from 26-28 • C [8, [14][15][16][17]. In banana plantations where the susceptible and widely cultivated varieties Prata and Nanica [6,18] are used, the incubation period for Mf could be as short as 13 to 14 days, whereas under unfavorable conditions, the pathogen's incubation period could extend to 35 days [4,14,[16][17][18]. For Mm, in planta epidemiological studies under controlled conditions indicated that spores germinate 2-3 h after deposition on banana leaves if a water film is present or if humidity is high [19].…”