Studies on Asian Soybeab Rust (Phakopsora pachyrhizi) in Argentina

CARMONA, M.A; GALLY M.; LOPEZ S E

FITOPATOLOGIA

Asociación Latinoamericana de Fitopatologia

Año: 2007 vol. 42 p. 25 - 30

ABSTRACT Asian rust caused by Phakopsora pachyrhizi was first detected in Argentina infecting soybean (Glycine max (L.) Merr.) in 2002.  Since then, the disease spread to the Northeast, Northwest and Pampeana regions. The objectives of this study were to characterize the pathogen morphologically and quantify P. pachyrhizi infection in soybean fields and kudzu (Pueraria lobata), the main alternative host, in 2003-2004 growing season. Rust incidence was 100 % in the three soybean fields evaluated. Disease severity was higher on the lower canopy both in soybean and kudzu. Number of pustules/cm2 varied from 72 to 232 in soybean and 42 to 78 in kudzu, and number of uredinia/lesion from 1 to 15 in soybean and 1 to 10 in kudzu. Telia were found in every soybean sample observed. Damage was not relevant due to the delay of epidemics but the disease represents a potential threat in some areas of the country.