International Fungicide Efficacy Trials for the Management of Soybean Rust

Abstract

The efficacy of fungicides in managing soybean rust was evaluated in 12 environments in South America and southern Africa over three growing seasons from 2002 to 2005. There were differences in final soybean rust severity, defoliation, and yield among the treatments at most locations. In locations where soybean rust was not severe, all the fungicides evaluated reduced severity. In locations where soybean rust was severe, applications of triazole and triazole + strobilurin fungicides resulted in lower severity and higher yields compared with other fungicides. The strobilurin fungicides provided the highest yields in many locations; however, severity tended to be higher than that of the triazole fungicides. There also were differences in yield and severity between the trials with two and three applications of several fungicides, with three applications resulting in less severe soybean rust and higher yields. However, the third application of tebuconazole, tetraconazole, and the mixtures containing azoxystrobin and pyraclostrobin was not needed to maintain yield. These fungicides were among the most effective for managing soybean rust and maintaining yield over most locations.

Adjuvant concentrations and uredospore densities on Phakopsora pachyrhizi infection efficiency in soybean

“…Several studies have evaluated the effect of fungicides in ASR control and quantified the reaction of cultivars to this disease (2, 11,12,18). On the other hand, there was no report in the available literature related to the assessment of spreader concentrations and uredospore density on infection efficiency and intensity of ASR.…”

Asian Soybean Rust – Meet a Prominent Challenge in Soybean Cultivation

“…In 2004 ASR was reported for the first time in the continental United States and since then it has attracted a lot of attention because of its potential to cause high yield losses within the corn belt in the Midwestern US (Schneider et al, 2005). In contrast to other soybean diseases no cultivars are available which can withstand all races of this pathogen, thus farmers rely on the costly use of fungicides to manage the threat (Miles et al, 2007). Because of its economical and ecological impact fungicidal treatments are seen critically.…”

Soybean Rust: Five Years of Research

“…For example, the control of frogeye leaf spot of soybean (Cercospora sojina) varied with applications of benomyl at different reproductive growth stages of the crop (Akem, 1995). To manage soybean rust with fungicides, three strategies include applying fungicides in a predetermined calendar-based schedule (Levy, 2005;Miles et al, 2007), scouting and applying fungicide after first detection of soybean rust, and utilizing a forecast system that monitors disease development in areas that are potential inoculum sources and applying fungicides ahead of a predicted deposition of spores. A calendarbased program with two or three applications provides the greatest level of yield protection; the crop is protected from flowering through grain fill; however, this may result in unnecessary fungicide applications that increase production costs and may have unforeseen consequences due to activity on non target fungi.…”

“…A calendarbased program with two or three applications provides the greatest level of yield protection; the crop is protected from flowering through grain fill; however, this may result in unnecessary fungicide applications that increase production costs and may have unforeseen consequences due to activity on non target fungi. Since the appearance of SR in the U.S. continental, studies were mostly conducted in the aim of finding the best fungicide, the right application time and the best way to do it (Mueller et al, 2009;Zhu, 2008;Miles et al, 2007).…”