Detection of soybean rust contamination in soy leaves by FTIR photoacoustic spectroscopy

In this work the Photoacoustic Infrared Spectroscopy from 4000 to 400 cm^-1 was applied, by the first time to our knowledge, to diagnostic the soy bean rust or Asian rust contamination on soy leafs caused by the fungi Phakopsora pachyrhizi. The obtained results shown that a premature, fast and precise diagnosis can be achieved using this technique before it can be detect by the conventional visual method. The early identification of the fungi infection avoid massive lost in the soy production and decrease the intense use of fungicide whose is necessary when the infection is in advanced stagy.