342 Journal oj Agricultural Research voi. xxx, No. 4 
the Santa Ana Valley on the roots of 
vines which had been brought from 
Missouri. He also reports the oc¬ 
currence of a species of Graphium in¬ 
festing diseased vine roots in the 
Santa Ana Valley but thinks that it 
bore no relation to the cause of the 
disease in question. 
Between this date and 1900 a few 
additional reports were made of grape¬ 
vine root rot. McCarthy (25, p. 122), 
discussing the disease in North Caro¬ 
lina, and Starnes (50, p. 282), in 
Georgia, both arbitrarily attribute it 
to Dematophora necatrix and Armillaria 
( Agaricus) mellea, merely because the 
same disease in Europe was commonly 
attributed to attacks by these fungi. 
Underwood and Earle (54, P . 272), 
discussing root rot of the grapevine in 
Alabama, state that it seems to be 
identical with the disease known as 
“pourridie” in France. They believe 
that it is quite prevalent and often 
does serious damage, as evidence of 
which they mention the fact that out 
of the 584 vines in the station vineyard 
all but 83 showed evident signs of the 
disease, and that many died during the 
late summer and fall. They note that 
the character of the soil apparently has 
much to do with the prevalence of the 
disease, that vines may live many years 
while more or less affected by it, and 
that some varieties are evidently much 
more resistant than others. Earle 
and Austin (14), writing four years 
later, give a much more detailed ac¬ 
count of grapevine root rot in Alabama 
and question the earlier statement of 
Underwood and Earle (54, P • 272) 
that this disease is the same as the 
“pourridiS” of the French, which they 
say is caused by Dematophora necatrix. 
Repeated attempts to isolate and 
culture the organism causing the 
whitish mycelial growth under the bark 
of diseased roots were unsuccessful 
and further observations led Earle 
and Austin to conclude that the dis¬ 
ease works much more slowly than the 
European root rot. These authors 
state that the mycelial whitening can 
often be found on old Scuppernong 
vines and on wild grapevines in the 
woods, although these are seldom if 
ever killed by it, and that its presence 
on the roots of cultivated vines is by 
no means a sure sign of immediate 
death. From an examination of the 
statistics on grape planting at the 
Alabama station these authors con¬ 
clude that the disease is a very serious 
one. They state that of the 651 vines 
alive or planted in 1894, a loss of 483, 
or 75 per cent, was sustained in six 
years and, although there was no proof 
that all of these were affected by root 
rot, they believe that the greater part 
of them died from this cause. These 
authors conclude that the Herbemont 
and Rulander varieties are immune 
and that the Delaware is very resistant 
to mortality from root rot. 
In 1901 Wilcox (58) described a 
rhizomorphic root rot of fruit trees 
which was causing widespread destruc¬ 
tion of orchards in Oklahoma and ad¬ 
jacent States. He demonstrates that 
this disease is caused by a species of 
Clitocvbe, which he describes as a new 
species, Clitocybe parasitica. In addi¬ 
tion to its occurrence on fruit trees, he 
finds the fungus to be a common para¬ 
sitic and saprophytic form on four 
species of oaks in Oklahoma. A rhizo¬ 
morphic root rot, w T hich Wilcox as¬ 
sumes was caused by this species of 
Clitocybe, is reported as occurring also 
in Texas, Missouri, southern Illinois, 
Indiana, and to some extent in Ohio, 
Georgia, California, and Oregon. Ex¬ 
cept for a few references in the bibli¬ 
ography appended, Wilcox makes no 
mention whatever of this disease on 
the grapevine, which, in some cases, 
undoubtedly is caused by the same fun¬ 
gus as that with which he was working. 
Walker (57, p. 30) and Hewitt and 
Hayhurst (21, p. 4@4) reported that 
root rot of fruit trees is widespread in 
Arkansas and causes serious damage 
in some localities. The first author 
says that, “besides the apple it affects 
probably all of the commonly culti¬ 
vated fruit trees, the grape as well as a 
number of forest trees,” and states that 
the disease is caused by toadstool 
fungi, “two of the forms concerned be¬ 
ing Clitocybe parasitica and Armillaria 
mellea.” 
Duggar (18, p. 4?1) mentioned the 
'abundant occurrence of Clitocybe para¬ 
sitica at Columbia, Mo., during favor¬ 
able seasons on roots of hickory and 
other deciduous trees, but failed to 
observe its occurrence in orchards, 
despite special effort to find it. The 
suggestion by some observers that 
Armillaria mellea is responsible for 
the root rot of fruit trees attributed to 
Clitocybe parasitica is refuted by Dug¬ 
gar, who states that he has never 
detected this fungus associated with 
the typical disease in Missouri. Al¬ 
though Armillaria mellea may occur in 
Missouri, and in this case be responsi¬ 
ble for some of the root rot reported, 
the writer has never seen it in the State 
even in forests where in favorable sea¬ 
sons Clitocybe parasitica often abounds. 
Butler (8, p. 24~89), in his account of 
root rot of grapevines in California, 
describes a slow and a rapid form of 
