Is tank mixing site-specific premixes and multi-site fungicides effective and economic for managing soybean rust? a meta-analysis
Soybean rust (SBR), caused by Phakopsora pachyrhizi, is controlled with sequential applications of commercial premixes containing two and, more recently, three site-specific fungicides. However, their efficacy has been reduced due to the development of fungicide resistance in the fungal population;...
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Veröffentlicht in: | Crop protection 2022-01, Vol.151, p.105839, Article 105839 |
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Zusammenfassung: | Soybean rust (SBR), caused by Phakopsora pachyrhizi, is controlled with sequential applications of commercial premixes containing two and, more recently, three site-specific fungicides. However, their efficacy has been reduced due to the development of fungicide resistance in the fungal population; hence the use of multi-site fungicides in tank mixing has been encouraged. In this work we used data from 45 uniform fungicide trials conducted across eight Brazilian states during three crop seasons (2014/15, 2015/16, and 2017/18) to identify scenarios when the practice of adding multi-site fungicides in commercial premixes was both technical- and cost-effective. Premixes of quinone outside inhibitor (QoI) + demethylation inhibitors (DMI) or succinate dehydrogenase inhibitors (SDHI) were applied alone, or tank mixed with multi-site fungicides. Three premixes (PICOxystrobin + CYPRoconazole, PYRAclostrobin + FLUXapyroxad and AZOXystrobin + BENZovindiflupyr) were tank mixed with one of three multi-site fungicides (+MANCozeb, +COPpeR oxychloride, and +ChLORothalonil). The benefits from tank mixing a multi-site tended to be highest for the least effective premix. Improvements in control efficacy (C‾, percent point; p.p.) and yield response (D‾, kg/ha) ranged from 3 to 15 p.p. and 58–240 kg/ha, respectively. The improvements in C‾ and D‾ were affected by severity in the non-treated check; significantly higher improvements in D‾ were determined in trials experiencing high SBR severity levels (>80%). The economic analysis for scenarios of soybean price and multi-site costs showed that the addition of +MANC, given its lower price, was more likely to be profitable compared with +CLOR and +COPR, particularly when tank mixed with the least effective commercial premix.
•The benefits from tank mixing a multi-site were the greatest for the least effective premix.•The improvements in control efficacy and yield were affected by disease pressure.•Tank mixing a multi-site was more beneficial in trials experiencing high disease pressure.•The addition of mancozeb, given its lower price, was more likely to be profitable than other protectants. |
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ISSN: | 0261-2194 1873-6904 |
DOI: | 10.1016/j.cropro.2021.105839 |