FLUXAPYROXAD IN THE ASIAN SOYBEAN RUST CONTROL IN THE CERRADO BIOME

ABSTRACT The etiologic agent of the Asian soybean rust is the Phakopsora pachyrhizi, which causes a reduction in the photosynthetic leaf area and, consequently, in the crop yield. Chemical control is one of the main measures for its management. The objective of this work was to evaluate the efficacy and selectivity of the fluxapyroxad fungicide on controlling the Asian soybean rust, under the edaphoclimatic conditions of the Cerrado biome. The experiment was conducted in an area under no-tillage system, in the Agricultural Research Center, Rio Verde, Goias, Brazil, during the 2012/2013 crop season, using the cultivar NA7337. A randomized block experimental design was used, with twelve treatments and four replications. The treatments consisted of applications of fluxapyroxad (FX), pyraclostrobin (PT), epoxiconazole (EX) and metconazole (MZ). The average severity of the disease in the plants reached 37% in the Control. All treatments with fungicides differed from the Control. Treatments 9, 10, 11 and 12 provided the greatest rates of soybean rust control. The treatments 10, 11 and 12 had the highest thousand grain weights, and the yields of the treatments 2, 3 and 11, despite higher than the Control, were lower than the treatments 4, 5, 6, 7, 8, 9, 10 and 12, which had statistically equal yields. The increasing in yield, compared to the Control, ranged from 10.05% (pyraclostrobin, epoxiconazole + pyraclostrobin + mineral oil) to 30.55% (pyraclostrobin, pyraclostrobin + fluxapyroxad + mineral oil and pyraclostrobin + metconazole + mineral oil). The highest rates of soybean rust control were presented by fungicides containing fluxapyroxad.

摘要
亚洲大豆锈病（Asian soybean rust）的病原物为豆薯层锈菌（Phakopsora pachyrhizi），该病菌可导致植株光合叶面积减少，进而降低作物产量。化学防治是该病主要的防控措施之一。本研究旨在评估氟唑菌酰胺（fluxapyroxad）杀菌剂在巴西塞拉多（Cerrado）生物群系的土壤气候条件下，对亚洲大豆锈病的防治效果与作物安全性。
试验于2012/2013生长季，在巴西戈亚斯州里奥韦尔迪市的农业研究中心免耕农田中开展，供试大豆品种为NA7337。试验采用随机区组试验设计，设置12个处理、4次重复，供试药剂包括氟唑菌酰胺（fluxapyroxad, FX）、吡唑醚菌酯（pyraclostrobin, PT）、环氧菌唑（epoxiconazole, EX）以及甲环唑（metconazole, MZ）。
对照组植株的平均病害严重度达37%，所有药剂处理组与对照组均存在显著差异。其中处理9、10、11和12对大豆锈病的防治效果最优。处理10、11和12的千粒重最高；处理2、3和11的产量虽高于对照组，但仍低于处理4、5、6、7、8、9、10和12，后者的产量无统计学显著差异。相较于对照组，各处理的产量增幅介于10.05%（吡唑醚菌酯、环氧菌唑+吡唑醚菌酯+矿物油）至30.55%（吡唑醚菌酯、吡唑醚菌酯+氟唑菌酰胺+矿物油及吡唑醚菌酯+甲环唑+矿物油）。含氟唑菌酰胺的杀菌剂对大豆锈病的防治效果最佳。