234 
qucnt conditions favorable to germination, and from tlie fact that the 
prevailing winds are from the southwest and naturally blow more 
spores to the north side of the tree.* It has already been noted that 
live-sixths of the infested points on the branches occur on the lower 
two-thirds. This is in harmony with the above facts, and arises from a 
like reason—the greater humidity on the shaded side. 
After the parasite has become well developed on the outer leaves in¬ 
fected from the terminal twigs and abundant spore clusters are formed, 
the foliage toward the center of the tree becomes infected. The para¬ 
site spreads from the terminal leaves to those at the base of the limbs, 
and the fall of the diseased foliage follows essentially in the same 
order, although as the basal leaves are the older their fall is in conse¬ 
quence somewhat hastened. 
From the preceding facts it will be seen that sprays applied after the 
outer leaves are infected, but before the fungus has matured fruit, may 
still prevent its spread to the main mass of foliage in the center of the 
tree. It is equally evident that if infection of the outer leaves is to be 
prevented the first application of fungicides should be made to the 
spore-bearing terminal twigs before the blossoms and new leaves have 
appeared. By this last method the spring infection of the leaves will 
be in the main pre veil ted and the fungicide on the terminal twigs will 
destroy the germinating spores that have been formed there. 
As it was not known in time that infection of the spring foliage was 
from the terminal twigs, the first application of sprays was not made 
until April 15, after the leaves Avere well formed. Hence some of the 
end leaves were infested before the fungicides were applied. In con¬ 
sequence of this a small proportion of these end leaves fell olf, but 
most of the foliage on the end shoots was retained, and nearly all of it 
over the major part of the tree. In applying the fungicides it was 
planned to have 2 treated trees alternating with 2 untreated ones. 
This gave control trees equal in number to those treated, while treated 
and untreated trees were equally representative of the whole. 
Two fungicides were used: 
(1) Ammoniaeal solution of eopper carbonate. The treated trees in 
the west half of the line received this spray, 
(2) Modified eau celeste. This ay as used for treatment of the trees 
in the east half of the line. These Avere mostly larger than those at 
the Avest, 
These two fungicides were made as followsi 
Ammoniaeal copper carbonate A —In a AYOoden pail 5 ounces of copper 
*Iibid., V.ol. Vii, No. 2, p, 69, 
tWhen copper carbonate can not be had of dealers it may be made at home, and 
usually at less than the market eost. For directions for making see Journal of 
Mycology, Vol. vu, No. 2., pp. 77-78. Also Farmers’ Bulletin No. 7, p. 12. The latter 
may be had from the Secretary of Agriculture. 
