Asian soybean rust (Phakopsora pachyrhizi) is an aggressive and destructive disease that undermines the current 34 million hectares of soybean production system in Brazil. The disease is present throughout the entire cultivated area. The disease control has required a combination of several practices in order to avoid losses. In the last 15 harvests, the application of fungicides has been shown as an effective alternative for the producer in the control of this aggressive disease. Since the first fungicides emergency recommended for the 2002/03 season (azoxystrobin, difenoconazole, fluconazole, pyraclostrobin + epoxiconazole, and tebuconazole), a large number of new formulations were added to the arsenal to control rust. There are today recorded in MAPA (Ministry of Agriculture and Supply) about 45 active ingredients (alone or in combination are about 120), trademarks, and formulations for the rational use against rust. Among fungicides, there are differences in efficacy, residual period, metabolic stability, and translocation rate, requiring care from the producer and technical assistance in the choice of the product to be used in each situation. In this review, the chemical control of rust is analyzed in Brazil from 2001/02 to 2013/14; its economic importance, strategic variables for the rational fungicides practice, factors that complicate the chemical control and the risk of resistance to the main chemical groups.
Part of the book: Soybean