February, 1890. 
33 
breCH RR P G Pi R D El N 
the usual number of bunches of fruit, and 
show no indicaticn of disease until about 
July, when the leaves begin to show that 
peculiar striped appearance, the fruit stops 
growing and by Fall the vine is bare of foli- 
age and full of half grown bunches of half 
grown grapes, worthless for any purpose. 
Vines thus affected will almost invariably 
be dead above the ground the following 
spring. A good many of the vines that were 
dead above ground last spring sprouted, 
either from the roots or from the main 
stock below the ground. These sprouts 
made good growth and appeared to be 
healthy for several weeks after starting; 
which led to the conclusion that the disease 
was in the top, not in the roots of the vine, 
and that by cutting off the dead stump and 
training up the most vigorous sprouts a 
good, new vine could be obtained in two or 
three years. This encouragement was short 
lived, however, for the new sprouts soon be- 
gan to show that characteristic, striped ap- 
pearance of the leaves that is an unmistak- 
able indication of the disease. 
EFFECT ON DIFFRENT VARIETIES. 
The Mission vines were first to show the 
effects of the disease, and the first to die 
from its influence. As a general rule the 
black grape vines were first attacked and 
yielded more readily to the disease than the 
white ones. The Mission vines were the 
oldest in this valley, which fact led to the 
conclusion that old vines were more suscep- 
tible to the disease than young ones. Sub- 
sequent observation showed that it was the 
variety, not the age of the vines that more 
readily yielded to its effect. As proof of 
this, I have a row of Mission vines four 
years old, all dead, by the side of Muscat 
vines, six years old, all alive. While some 
varieties withstand the attack of the disease 
longer than others, no vine — not even the 
wild vines of the mountain and canyons — 
is exempt from it. Some of the wild vines 
are very old, one in this vicinity measures 
eighteen inches in diameter and spreads all 
over the top of a large tree. It is now badly 
affected by the disease and will probaby 
never again put on its foliage. A Mission 
vine up the Santa Anna River, planted on 
the birthday of one of the oldest Spanish 
residents— now eighty year sold— died in 1887. 
CONDITIONS WHICH APPEAR TO BE FAVOR- 
ABLE TO THE DISEASE. 
No condition is exempt from its attack. It 
appears on vines from the low lands near 
the coast to high altitudes in the mountains; 
on vines protected by trees and hedges 2 •_ . 
every point of the compass; in all kinds of 
exposure to sun and winds ; on all kinds of 
soil, from the heaviest clogs and adobe to 
the lightest sediment and pure sand ; under 
all kinds of cultivation and training of the 
vines; on vines thoroughly and annually 
irrigated and on those never irrigated; it 
appears in the “vineyard of the slothful all 
grown up to weeds,” and in those of clean 
and thrifty culture. If there be any condi- 
tion, more or less subject to its attack, a 
j ear’s close observation of the vineyardists 
here has failed to discover it.” 
Conducted by A. B. Cordley, 
Agricultural College, Michigan. 
Arsenical Spraysfor the Plum Curcullo. 
Next to the introduction of the Australian 
Lady -bird, economic entomology has per- 
haps done nothing during the last two or 
three years more important than in calling 
the attention of fruit growers to the value 
of the arsenites in the curculio warfare. 
Since Prof. Cook first demonstrated their 
value in destroying the codling larva, the 
arsenites have become almost indispensable 
aids to horticulture, yet they have been 
used against the curculio but very little. 
First — Because it was supposed that they 
would be useless, as the egg is laid within 
the fruit and hence the larva when hatched 
is beyond the reach of poisons. Second — 
Early experiments in this fine were failures 
through lack of thoroughness. 
Two years ago we sprayed both cherry 
and plum trees three times, June 6th, June 
12th, and June 20, with one pound of Lon- 
don purple to one hundred gallons of water 
(a mixture which we now consider twice 
too 3trongj and none of the cherries and 
but few of the plums were stung. The 
foliage of the plum trees was not injured 
even by this strong mixture, but after the 
second spraying, the foliage on the cherry 
trees was somewhat burned, and after the 
third treatment the injury was severe. 
Prof. C. M. Weed, of the Ohio Experi- 
ment Station, has obtained equally good re- 
sults. After carefully conducting extensive 
experiments for two years, he states that 
apparently “three fourths of the cherries on 
the sprayed trees, liable to injury by plum 
curculio, were saved by the treatment with 
London purple ” Mr. Pain, a fruit-grow T er of 
South Haven, Mich., reports having spray- 
ed plum trees, last season, with one pound 
of Paris gr< en to two hundred gallons of 
water, and that forty-eight hours after- 
ward, he found on jarring the tree that 
three-fourths of the beetles that fell were 
dead. 
These experiments, and many others 
that we could cite, seem to show conclus- 
ively that the curculio can be successfully 
destroyed with the arsenites. The questions 
now to consider are; which one of the 
arsenites shall we use, how strong shall we 
use it, and when shall we apply it, to be the 
most effective and yet produce the least 
injury to the foliage. Many are, as we be- 
lieve unwisely, advocating the use of white 
arsenic on the ground that it is cheaper to 
buy the pure arsenious acid, than to buy it 
in combination with other substances as 
in Paris green or London purple, and that 
they can get a more uniform article. Even 
admitting these suppositions to be true, we 
still believe it unwise to use white arsenic. 
It is more dangerous to handle and is more 
injurious to foliage. The arsenious acid in 
Paris green is in combination with copper 
and is very insoluble, while that in London 
purple is slightly more so. Both these sub- 
stances remain in suspension in water, and 
if thrown upon foliage in moderate quanti- 
ties, produce but little injury under ordinary 
circumstances. If rain follows, however, 
soon after spraying, something in the rain 
water, probably the ammonia, seems to ren- 
der the arsenious acid more soluble. It is 
dissolved, enters the tissue of the leaf, and 
the foliage is burned. White arsenic, being 
more soluble does not need the agency of 
rain in its destructive work. Spray it upon 
a tree in any proportion, provided it is strong 
enough to kill the curculio, and enough of 
it is almost certain to be in solution to injure 
the foliage. In our opinion Paris green is 
perferable to London purple, for the same 
reason that the latter is to be preferred to 
arsenic, i. e. less of the arsenious acid is 
soluble. 
The question in regard to how weak a 
mixture we can use and still be effective, 
is more difficult to answer. Until last sea- 
son we have noticed but little injury to 
foliage from using one pound of London 
purple to one hundred gallons of water, but 
results from all over the country the past 
season show that we cannot safely use so 
strong a mixture. We sprayed both cherry 
and plum trees, at various times, from May 
20th to June 12th, with London purple, the 
strength of the mixture varying from one 
pound to one hundred gallons to one pound 
to two hundred gallons of water, and the 
foliage was injured but slightly, if at all. 
June 24th we sprayed peach, apple and 
plum trees with one pound of London pur- 
ple to one hundred gallons of water. Rain 
followed the next day and the injury was 
severe. From July 5th to July 10th we 
sprayed peach, pear, and cherry trees with 
one pound of London purple to two hund- 
red gallons of water, and in every case the 
foliage on the peach trees was badly in- 
jured. July 11th we sprayed peach trees 
with Paris green, using one pound to one 
hundred, to two hundred, to two hundred 
and fifty, and to three hundred gallons of 
water. In the first proportion, the injury 
to the foliage was slight; in the others none 
at all. These experiments seem to show: 
First, that London purple is much more 
injurious to foliage than is Paris green. 
Second, that peach foliage is much more 
susceptible to injury than is that of the 
pear, apple, plum or cherry. Third, that 
we may spray pear, apple, plum and cherry 
trees, with London purple, but should not 
use it stronger than one pound to one hun- 
dred and fifty gallons of water. Fourth, 
that if we use the arsenites on peach trees we 
should use Paris green and should not use 
over one pound to two hundred and fifty 
gallons of water. 
The question now arises, will these 
strengths be effective? Prof. Forbes has 
found in some breeding cage experiments, 
that four days after spraying foliage with 
Paris green in various proportions, the re* 
