Mar. 6, 1917 
Little-Leaf of the Vine 
393 
and Fresno and by thousands of vines distributed by nurserymen. 
The evidence seems conclusive that the cause is local, whether it exists 
in soil, water, or weather conditions. 
VARIATIONS IN SUSCEPTIBILITY 
The disease has been noted on various species of Vitis, and none has 
proved immune. It has been found on the following phylloxera-resist¬ 
ant stocks: Riparia gloire de Montpellier, Rip. grand glabre, Rupestris 
St. George, Vitis aestivalis, V. Champini, V. Doaniana, Berl. X Rip. 
157-11, Rip. X Rup. 101-14, 3306, 3309, Rip. X Cord. X Rup. 106-8. 
Sol. X Rip. 1615, 1616. 
All varieties of Vitis vinifera are attacked, so far as noted; but a few 
appear to be peculiarly susceptible and a few others to have some con¬ 
siderable degree of resistance. The Mataro is so badly affected as to 
make a class by itself, although the Carignane is almost as bad. 
Examples of partial resistance have been noted with Black Prince, 
Burger, Sultanina, Valdepenas, Petite, and Alicante Bouschet. A vine¬ 
yard of Mataro was found with all the vines nearly dead, except a few 
score scattering Black Prince vines which appeared perfectly healthy. 
Healthy Valdepefias vines have been found in similar positions sur¬ 
rounded by badly affected vines of other varieties. Blocks of Sultanina, 
Burger, and the Bouschets, showing but negligible signs of disease, are 
growing adjacent to badly affected blocks of Carignane and other varie¬ 
ties. No badly affected vineyards or vines of these varieties have been 
found. 
Badly affected vines in considerable quantities have been noted of 
Muscat, Tokay, Palomino, Feher Szagos, Zinfandel, Malaga, Green Hun¬ 
garian, and Grenache. 
Grafted vines seem to be as susceptible as vines on their own roots. 
The effect of grafting very susceptible or less susceptible varieties, and 
vice versa , has not been tried. 
OTHER PLANTS AFFECTED 
Several kinds of trees, differing very much botanically among them¬ 
selves and from the vine, are affected by what seems to be the same 
trouble. This fortifies the idea that the disease is not infectious or 
parasitic. The location and distribution of the diseased trees are exactly 
parallel to those of the diseased vines, indicating a common cause. The 
Carolina poplar seems particularly susceptible, showing the small, pale 
leaves, abnormally numerous small branches, and generally stunted 
condition in a very marked degree. On affected poplars very remark¬ 
able examples of fasciation of the branches are common. Copious irri¬ 
gation was noted in one case to increase the growth of these trees, but 
without apparently diminishing the other symptoms. 
