Mycosphaerella leaf disease (MLD) outbreak on Eucalyptus globulus in Brazil caused by Teratosphaeria (Mycosphaerella) nubilosa

Abstract

Severe defoliation of young plantations of Eucalyptus globulus trees showing symptoms resembling Mycosphaerella leaf disease was observed in the province of Rio Grande do Sul, Brazil. The serious primary pathogen, Teratosphaeria nubilosa (= Mycosphaerella nubilosa) was repeatedly isolated from leaf spots and blotches on both juvenile and adult foliage and its identification was confirmed with DNA sequence comparisons. This pathogen was recently introduced into Uruguay and this report suggests a rapid range expansion in South America. Further spread of T. nubilosa northwards into Brazil’s main Eucalyptus-growing areas as well as to other South American countries is probable and research towards developing resistant planting stock should be a priority in South America.