Greenhouse and field evaluations of melon (Cucumis melo L.) for resist
ance to gummy stem blight, caused by the fungus Didymella bryoniae (Au
ersw.) Rehm, were conducted on 798 U.S. Dept. of Agriculture Plant Int
roduction (PI) accessions and 24 related Cucumis species. Plants were
inoculated at the three to four true-leaf stage with a virulent isolat
e of D. bryoniae collected from Onondaga County, N.Y., and disease ind
ices were calculated based on foliar and stem symptoms. In greenhouse
screens, 43 C. melo accessions showed a high level of resistance. Resu
lts were consistent between the optimized greenhouse screening procedu
re described and inoculated replicated field tests, Of these accession
s, a Chinese group, PIs 157076, 157080, 157081, 157082, 157084; anothe
r group from Zimbabwe, PIs 482393, 482398, 482399, 482402, 482403, 482
408; and some others from different origins, PI255478 (Korea) and PI 5
11890 (Mexico), showed high levels of resistance, at least equal to th
at in PI 140471, the leading source of resistance to date.