233 
strated that the disease may be controlled at moderate expense and 
in a thoroughly satisfactory manner. The suggestions of B. T. Gallo¬ 
way in regard to the treatment of this disease have proven of value.* 
From experiments now completed, and from additional facts gathered 
in relation to the habits of the parasite, there may now be outlined a 
very satisfactory plan of treatment. 
The trees selected for the experiments were on the place of J. S. 
Baldwin, about 1 mile east of the village of Orange. They were badly 
infested by Cercospora in 1891, and had lost nearly all of their foliage 
by the latter part of July. By the 1st of August, 1892, the untreated 
trees were in worse condition than at the same date the preceding 
year, and only a few shoots had developed during the spring. There 
were 34 trees included in the experiment, and they formed a single 
row about 800 feet long, running from west to east through an orchard 
composed of various fruits. They were twelve years old and were 
grown on a soil of gray loam mixed with more or less gravel.* The 
care given them has been but moderate. Many of the tops were 
well formed and of good size, while others were smaller and stunted 
in growth, owing to poorer soil. The branches, with the exception of 
a few terminal ones, were alive, but up to August 1 but little growth 
had been made and most of the wood of last season’s growth was 
ready to die back. These trees leafed out fully in the spring of 1892 
and received the first treatment in April. 
Prior to the beginning of this season’s work the almond foliage was 
supposed to be annually infected in the early spring by spores which 
came mainly from the fallen leaves of the previous year’s growth. It 
has since been learned that infection of the spring foliage is mainly 
accomplished by means of spores produced on the terminal twigs of 
the tree, i. e., on the last season’s shoots. There is some evidence also 
that Cercospora may become nearly or quite biennial in its habits when 
living on almond branches. It even appears probable that in some 
cases it lives in the tissues of the twig through the mild winters of south¬ 
ern California and produces in the following spring a sufficient number 
of spores to infect the new foliage. Some observations seem to point 
to even a perennial life for the fungus, in rare cases. Be this as it 
may, it is evident from the way the tree first shows the disease in the 
spring that the new terminal leaves are infected directly from the last 
year’s wood. Branches on all parts of the tree show disease first on 
the leaves at the end. This is as true of the uppermost limbs as of 
those next the ground, Avhicli would not be the case if the infecting 
spores came from either fallen foliage or the soil. 
The spring infection is usually general over the outer branches, but in 
many cases it is more complete and the work of the fungus shows earlier 
on the north than on the south side of the tree. This may arise in part 
from the greater humidity on the north, due to shade, and the conse- 
*Ibid., pp. 77-78. 
