12 
AuaMi^'vvwvwt i mwmii v mi u u uiw m o 
/"ORCHFVRD 
GARDEN 
January, 1890 
Conducted bt prof. F. Lamson Scribner, 
Botanist, Experiment Station, Knoxtille, Tenn. 
Root-rot of llio Vine. 
Very little has been said or published in 
this country about the Vine Root-rot, a 
disease long known in Europe, where it has 
been carefully studied by German, French 
and Italian investigators. Our own obser- 
vations have led us to the conclusion that it 
is by no means an uncommon disease here, 
at least in the Southern districts. It was 
first discovered in a vineyard near St. Louis, 
Mo., by Professor Viala, in 1887, and in 
company with this learned viticulturist we 
found it in northeastern Texas and again 
in Napa valley. California. During the past 
season we have seen a number of vines 
which were nearly or quite dead from this 
same disease, here in the vicinity of Knox- 
ville. 
The roots of vines may decay through acci- 
dental or mechanical injury or on account 
of some physiological disorder, but the dis- 
ease we are considering is caused by the at- 
tack of a fungus, or rather by the attack of 
fungi — for more than one of these plant 
pests may produce the disease — and, as a 
vine once infested is doomed to destruction, 
and as infection may spread through the 
ground from one vine to another, grape 
growers ought to learn to recognize the 
malady that they may adopt measures to 
prevent it or check its progress. 
The fungi which, in Europe, have been 
positively identified as the cause of Root- 
rot of the vine are Agaricus melleus and 
Dematophora necatrix. The conditions un- 
der which the disease appears and the char- 
acters presented by the vines affected ob- 
served in this country are identical with 
those occurring in Europe, and although 
we have not followed the fungi seen here 
through all their stages of development, 
we have little hesitation in pronouncing 
them the same as those above named. For 
the practical purposes of the vinevardists 
there is certainly no distinction to be made. 
The first, Agaricus melleus, we have seen 
on vine roots in California, while all the 
affected vines observed here in the East ap- 
pear to have been attacked by the second, 
Dematophora necatrix. The latter is gener- 
ally conceded to betbe more common cause 
of Vine Root-rot. These fungi are both para- 
sitic and saprophytic in then habits, i. e., 
they may attack healthy roots and after 
chese have been killed, live upon their de- 
caying remains. They appear to have the 
power of living, for a time at least, upon 
whatever vegetable mold there may be in 
the soil, and from this spreading to the liv- 
ing roots cf plants coming within their 
reach, for their attacks are not limited to 
the vine ; they are known to have the power 
of infesting a number of our fruit and 
forest trees and even some of the field and 
garden vegetables, as the potato, beet, etc. 
Vines diseased with Root-rot exhibit no 
characters above ground which might not 
appear from any other injury of the roots ; 
the effect upon the vine as well as the man- 
ner in which the disease spreads in a vine- 
yard is the same as in the case of the 
Phylloxera or root-louse. The first effect is 
the production of an excessively abundant 
crop. Then the vines exhibit an enfeebled 
condition ; the shoots push forth, usually 
numerous, remain slender and short ; the 
leaves are small and usually more deeply 
cut than is normal, and within a year or 
two the vines die. In experiments made 
by Viala upon young vines in pots these 
died six months after being infected with 
fungus ( Dematophora .) The roots become 
spongy, of a dark brown color in the in- 
terior, and finally decompose. 
agaricus Melleus. Fig. 1485. 
Root-rot appears most frequently in clayey 
or marly soils where there is standing water, 
and in those havmg an impermeable sub- 
soil. It often appears in little depressions 
in a vineyard where water accumulates and 
remains for a considerable time, other and 
dryer parts of the same vineyard being en- 
tirely free from the disease. Excess of 
moisture in the soil is one of the chief con- 
ditions favoring Root-rot. In sandy or 
granitic soils overlying a porous subsoil, or 
which may be well drained in other ways, 
the disease rarely appears and never with 
any great severity. It is most likely to 
appear in vineyards planted on newly 
cleared forest lands, especially after oaks, 
as in the case observed by us in California. 
The influence of temperature on the de- 
velopment of Root-rot is secondary to that 
of moisture ; however, it progresses most 
rapidly when the temperature ranges be- 
tween 70 and 80 degrees F. 
The mature or fruiting state of Agari- 
cus melleus, shown in figure 1485, is com- 
parable to that of the common mush- 
] 
room, and like that fungus it is edible. We 
have seen this state in the vicinity of Wash 
ington, D. C., and, in most luxuriant de- 
velopment, in oak forests near Dallas, Tex- 
as. The color of the cap which may be from 
| 3 to 6 inches in diameter, is a clear brown- 
ish yellow, becoming more brown with age. 
Over its surface are scattered small, brown- 
ish, hairy scales, and on the under side are 
numerous thin radiating plates (gills) which 
i are white spotted with dull red. On these 
the spores are borne. 
The mycelium of this fungus forms much 
branched, root-like cords, cal- 
ed rhizomorphs, that are very 
dark brown on the outside and 
white within. These rhizo- 
morphs, growing through the 
soil meet roots of the vine, pen- 
etrate the bark of the latter be- 
tween which and the wood 
they continue their growth re- 
maining as slightly flattened 
cords, distending and even 
rupturing the bark over them, 
or spreading out into thin felt- 
like plaques, often of consider- 
able extent, and with elegant 
fringe-like borders. These flat 
expansions are whitish in col- 
or, and show a marked phos- 
phorescence in the dark. We , 
have seen the rhizomorphs fol- 1 
lowing the irregularities of the 
vine roots, embedding them- 
selves under the bark and re- 
appearing upon the surface 
again farther on, as illustrated 
in figure 1622. The finer my- 
celial filaments p«netrate into A piece ofvlne 
all parts of the roots causing ro ,°' a ® ect ®d 
. . “with Pourrl- 
their final decomposition. die” on the sur- 
face of which 
The other fungus to which 8 !: 0 ! he “ cords " 
u . “ -r. of Agaricus 
we have referred — Dematopho-meXieu* (after 
ra necatrix— lives upon a great ic'ilf rdet ’ ) Fig ' 
number of fruit trees and other plants* 
which are destroyed by its attacks. The 
fruiting stage of this fungus is very unlike 
that of the Agaricus. The spores are borne 
upon the termi n al branches of little bundles 
of filaments (see figure 1623) that are scarcely 
more than one-fiftietli 
of an inch high. These 
under favorable con- 
ditions are produced 
in great abundance 
and the number of 
spores they yield is 
enormous. Roots of 
the vine attacked by 
this parasite present, 
between the bark and 
the wood, felt-like 
plaques composed of 
matted mycelial 
threads. This mycel- 
ium penetrates to the 
pith through the wood 
rays (medullary rays) 
and like the Agaricus, spore-bearing fruiting 
„ „ . stalks of Dematophora 
finally causes the de- necatrix (after Hartlg.) 
composition of the roots. Lik e the Aga- 
