The origin of the disease was still uncertain however, in 1927, Raymond suggested that the disease may have been caused by a fungus identified in 1877 in Portugal that had been imported from Portuguese colonies.
A orixe da doenza era daquela descoñecida, aínda que en 1927 Raymond suxestionara que a patoloxía podería ter sido causada por un fungo identificado en 1877 en Portugal que probabelmente se importara das colonias lusas.