The causal agent of a foliar disease of garlic (Allium sativum) was id
entified as Stemphylium vesicarium (Wallr.) Simm. Disease symptoms wer
e reproduced on garlic leaves 8 to 10 days after inoculation in a gree
nhouse (temperature range 22-26 degrees C). Onion and tomato, two prev
iously reported hosts of S. vesicarium, were also artificially infecte
d with the isolate from garlic. This is believed to be the first repor
t of S. vesicarium causing a severe leaf blight of garlic in the New W
orld area.