Asian soybean rust in Brazil: past, present, and future

Abstract

-Asian soybean rust, caused by the fungus Phakopsora pachyrhizi, is the most severe disease of the crop and can cause yield losses of up to 90%. The disease was first reported in Brazil in 2001. Epidemics of the disease are common in the country, where the fungus can survive year-round. Regulatory measures to reduce the inoculum between seasons and avoid late-season soybean have been adopted to manage the disease. Disease control has relied mainly on chemical control, but a lower sensibility of the fungus to fungicides has been reported in Brazil. Major-resistance genes have been mapped and incorporated into the cultivars. With the reduced efficacy of the fungicides, the adoption of integrated measures to control the disease will be important for the sustainability of the crop. This review presents the main changes in the soybean crop system caused by the introduction of the fungus in Brazil, the current management strategies adopted to avoid losses, and the new trends that, together with biotechnological strategies, can improve management in the future.Index terms: Glycine max, Phakopsora pachyrhizi, biotechnology, chemical control, genetic resistance, losses, management. Ferrugem-asiática da soja no Brasil: passado, presente e futuroResumo -A ferrugem-asiática da soja, causada pelo fungo Phakopsora pachyrhizi, é a doença mais severa da cultura e pode causar perdas de produtividade de até 90%. A doença foi relatada pela primeira vez no Brasil em 2001. Epidemias da doença são comuns no País, onde o fungo pode sobreviver durante todo o ano. Medidas regulatórias para reduzir o inóculo entre safras e evitar a semeadura tardia de soja têm sido adotadas para manejar a doença. O controle da doença tem se baseado principalmente no controle químico, mas uma menor sensibilidade do fungo aos fungicidas tem sido relatada no Brasil. Genes de resistência têm sido mapeados e incorporados às cultivares. Por causa da redução da eficiência dos fungicidas, a adoção de medidas integradas para o controle da doença será importante para a sustentabilidade da cultura. Este artigo de revisão apresenta as principais mudanças no sistema de produção da soja causadas pela introdução do fungo no Brasil, as medidas de controle atualmente usadas para evitar perdas, e as novas tendências que, juntas com estratégias biotecnológicas, podem melhorar o manejo da doença no futuro.Termos para indexação: Glycine max, Phakopsora pachyrhizi, biotecnologia, controle químico, resistência genética, perdas, manejo.

Pathogenic Variation of South American <i>Phakopsora pachyrhizi</i> Populations Isolated from Soybeans from 2010 to 2015

“…Although the use of fungicides is a major measure to control the disease, production costs increase considerably with such use due to the cost of the chemicals and application management (Godoy et al 2016). Furthermore, reduced sensitivity of rust isolates to the fungicides has been observed in Brazil (Godoy et al 2015), most likely due to the extensive and repeated use of fungicides.…”

Sensitivity of two isolates of Phakopsora pachyrhizi to dithiocarmamate, chloronitril, triazoles, strobilurins, and carboxamides fungicides

“…The Asian soybean rust (ASR), caused by the phytopathogen Phakopsora pachyrhizi (Sydow & Sydow), is a fungal disease distributed worldwide responsible for causing severe damage to soybean crops [Glycine max (L.) Merril], leading to yield reduction of up to 90% (YORINORI et al, 2005;HARTMAN et al, 2015;GODOY et al, 2016a). Since the introduction of this endemic fungus in Brazil, ASR has had negative economic impacts on soybean production, demanding approximately US$ 2 billion per year for its control (GODOY; BUENO; GAZZIERO, 2015).…”

Effects of foliar nickel (Ni) application on mineral nutrition status, urease activity and physiological quality of soybean seeds

“…According to Moraes et al (2010), under Brazilian environmental conditions, soybean yield increased approximately 300 kg ha -1 when plants were sprayed with 50 g ha -1 of Ni. The increase in soybean yield by the foliar application of Ni can be attributed to the effect of Ni on reducing symptoms of fungal infection (Reis et al, 2014;Godoy et al, 2016;Langenbach et al, 2016).…”

“…Another important aspect of seed production refers to the plant's vitality, and the physiological quality of seeds. In order to improve both it is common to apply foliar fungicides for fungal soybean disease control (Godoy et al, 2016).…”