Abstract

Brazil is the first soybean producer in the world, and the largest exporter. In the 2019/20 harvest, the country produced about 124.85 million tons, representing 30% of world production. Global soy production for 2019/20 reached 337.9 million tons. Asian soybean rust (ASR) is the most pathogen on soybean in Brazil in nowadays. Target spot and Septoria leaf spot plus white mold complete these scenarios. ASR emerged in Brazil in 1979. The use of fungicides in the soybean crop in Brazil intensified after the master of 2002 with the resurgence of soybean rust, where the use of triazoles intensified. The massive sprays to pathogen control reached 3.5 sprays per season. In 2006, the first reports of loss of sensitivity of the fungus to the group appeared, notably for the fungicide flutriafol and tebuconazole used in many situations in a curative way or to eradicate the fungus. From that moment on, the productive system sought to use triazoles and strobilurins. In 2011 came the first reports of loss of sensitivity of the fungus in the group of strobilurins. This fact was due to the use of pyraclostrobin in the vegetative phase of soybeans without protection by multisite. That same year, the introduction of the active ingredients in copper oxychloride, mancozeb and chlorothalonil took place in Brazil. In 2015, the first carboxamides ((benzovindiflupyr) (solatenol and fluxpyroxade) associated in triple mode with triazoles and strobilurins were launched on the Brazilian market. Due to the specific mode of action in the metabolism of the fungus (biosynthesis of ergosterol (triazoles), mitochondrial respiration in the cytochrome oxidase enzyme complex - QOIs (strobilurins) and succin dehydrogenase - SDHIs (carboxamides), the need for their association in the sprayings was seen. To multisite (cuprics, dithiocarbamates and nitriles). For the sustainable management of the disease in Brazil, control strategies are recommended, such as the use of systemic fungicides, with a specific biochemical mechanism of action with the adoption of tank mix with multisite, adoption of cultural practices (sanitary emptiness) and sowing schedule and the use of varieties with quantitative resistance (partial or horizontal resistance). These measures will guarantee the sustainability of the culture and the useful life of systemic fungicides or specific sites.

Highlights

  • The potential of the soybean crop yield can be affected by several factors, among which stand out the soil fertility, water availability during the harvest, the plant population, the sowing time, the productive potential of the cultivar, the occurrence invasive plants, pest infestation and diseases [14, 15, 17, 55]

  • It is well known that sowing in February would not enter the sanitary void and would allow the farmer to make his seeds of quality and at a lower cost compared to the month of December, which would remain within the calendar and without advancing in the sanitary void, as happens in the states of Tocantins (Lagoa da Confusão) and Goiás (Luis Alves and São Miguel do Araguaia), where large seeders harvest their seeds in September–October and advance in the Brazilian sanitary vacuum

  • The main groups of fungicides registered for the control of Asian soybean rust (ASR) are: demethylation inhibitors (DMI’s - tebuconazole, cyproconazole, protioconazole, epoxiconazole and others); quinone oxidase inhibitors (QoI’s - azoxystrobin, trifloxystrobin, picoxystrobin and pyraclostrobin), succinate dehydrogenase inhibitors (SDHI’s - fluxpyroxade, bixafen and benzovindiflupyr), cupric, nitriles (e 3), until the year 2020

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Summary

Introduction

Soybean [Glycine max (L.) Merrill] is one of the ten most economically important crops worldwide, as it is one of the main sources of protein concentrates and vegetable oil [25]. For the sustainable management of the disease in Brazil, control strategies are recommended, such as the use of systemic fungicides, with a specific biochemical mechanism of action with the adoption of tank mix with multisite, adoption of cultural practices (sanitary emptiness) and sowing schedule and the use of varieties with quantitative resistance (partial or horizontal resistance). These measures will guarantee the sustainability of the culture and the useful life of systemic fungicides or specific sites [155]

Damage caused by Asian soybean rust (ASR)
Losses
Chronology of the disease
Host of the pathogen
Symptoms of the disease
Causal agent of the disease
Conditions that favor the disease
Disease control
Cultural control
Genetic resistance
11. Chemical control
12. Risk factors for the use of fungicides with specific mode of action
13. Use of triazoles to control Asian soybean rust
14. Reduction of the sensitivity of Phakopsora pachyrhizi to triazole Fungicides
16. Emergence of proticonazole from the DMI’s group
17. Introduction of the dithiocarbamate group to control Asian soybean rust
Findings
18. Conclusions
Full Text
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