Rw. Barreto et Hc. Evans, FUNGAL PATHOGENS OF EUPHORBIA-HETEROPHYLLA AND EUPHORBIA-HIRTA IN BRAZIL AND THEIR POTENTIAL AS WEED BIOCONTROL AGENTS, Mycopathologia, 141(1), 1998, pp. 21-36
A two-year survey of the fungi associated with two important congeneri
c pantropical weeds, Euphorbia hetero-phylla and E. hirta, was conduct
ed in part of their native range in southern Brazil. Sampling was conc
entrated mainly in Rio de Janeiro State and ten species were identifie
d as pathogens of these weeds. Two taxa, Botrytis ricini and Uromyces
euphorbiae, were common to both weed hosts. Alternaria euphorbiicola,
Bipolaris euphorbiae, Melampsora sp., Oidium sp. and Sphaceloma poinse
ttiae were recorded only from E. heterophylla, whereas Colletotrichum
gloeosporioides, Sphaceloma sp. and Sphaerotheca filliginea were restr
icted to E. hirta. Botrytis ricini and Colletotrichum gloeosporioides
are new records for E. hirta, and Alternaria euphorbiicola and Sphaero
theca fuliginea are new host records for Brazil. Bipolaris euphorbiae,
previously identified as Helminthosporium sp., is considered to be th
e correct name for the causal agent of a major disease of E. heterophy
llum in Brazil. The potential of these pathogens as biocontrol agents
is discussed and the mycobiota associated with both these weeds worldw
ide is reviewed.