In Brazil, soybeans are traditionally sown in rows spaced from 45 to 50 cm. Changes in such a spacing may alter the microclimate and the efficiency of fungicide application. This study aimed to verify the influence of different row spaces on the severity of soybean rust and on the grain yield of soybean cultivars BRS 256 RR, BRS 246 RR and BRS 318 RR, respectively, in 2007/2008, 2009/2010 and 2010/2011 crop seasons. Four row spaces (35, 45, 55 and 65 cm) were tested, with and without fungicide spraying over the shoot of plants. The efficiency of fungicide spraying was confirmed for disease control in the three crop seasons and row spacing was not significant for any variable assessed in the first crop season, when the disease started before flowering. In the second and third crop seasons, when the disease started during full flowering and the severity was lower than in the first crop season, row spacing influenced the yield in plots without fungicide for cultivar BRS 246 RR (second crop season) and the disease severity for cultivar BRS 318 RR (third crop season).
plant arrangement; Phakopsora pachyrhizi; Glycine max; cultural control
