LITTLE-LEAF OF THE VINE 
By Frederic T. Biodetti and Leon Bonnet, 
California Agricultural Experiment Station 
OCCURRENCE OF THE DISEASE 
A disease of the vine (Vitis spp.) known variously as “little- 
leaf “curly-leaf,” and “yellow-leaf” first attracted attention in 
California about the beginning of the century. Some growers claim to 
have noticed it earlier, but no printed reference has been found that 
points clearly to this disease before 1900. It seems probable that it was 
present earlier, but most of the vines in many districts where it is preva¬ 
lent have been planted since that date. This may account for the appar¬ 
ent spread and increase of the disease during the last 10 or 15 years. 
At present, many vines are attacked in various regions, from the 
borders of Sacramento and San Joaquin Counties to the southerly end of 
the San Joaquin Valley. No indubitable cases have been noted in the 
Sacramento Valley, south of Kern County, or in any part of the coast 
region. The total area attacked is difficult to estimate, but it is large. 
In some localities, only occasional vines or small spots are affected; in 
others, most of the vines show more or less intense symptoms. 
LOSSES 
The loss in crop is also large and equally difficult to estimate. In 
some regions the affected spots are fairly definite, the vines badly injured, 
and the crop almost a total failure. These regions, however, represent 
the smallest part of the loss. Where the disease attacks the vines with 
great severity, if the affected spots are large, the whole vineyard is usually 
abandoned. It is only where the diseased spots are small that they are 
allowed to remain. The greatest loss occurs in the vineyards where the 
disease appears in a milder form and is distributed over wide areas. In 
such cases the crop may be diminished one-half, one-third, or less. The 
total loss of crop for California from little-leaf is considered by some 
observers to be greater than that due to any other vine disease. This is 
probably an exaggeration; but undoubtedly it takes rank with mildew, 
vine hoppers,* and phylloxera as one of the most destructive. 
GENERAL CHARACTER OF THE DISEASE 
A vine, when very slightly affected, shows nothing but a few lightish 
areas or broad stripes on some of the larger leaves near the middle of the 
cane. These are not very noticeable and appear to be due to a slight 
deficiency of chlorophyll in the parts affected. On such vines the crop 
Journal of Agricultural Research, 
Washington, D. C. 
w 
Vol. VIII, No. 10 
Mar. 6, 1917 
Key No. Cal. — 9 
