22 
BULLETIN 837, U. S. DEPARTMENT OE AGRICULTURE. 
The burning was closely related to the thrift of vines, the stage 
of grape growth when sprays were applied, the weather during and 
following spray aplications, and the method of mixing materials. 
Weak vines and those bearing too heavy crops were most seriously 
burned. Spray applications just before and after bloom caused 
more injury than later applications. Excessively wet and cloudy 
weather during and following spray applications appeared to in- 
crease burning. When either of the ingredients of Bordeaux was 
added to the other without being diluted, increased burning resulted. 
From the above observations it is concluded that Bordeaux mixture 
should not be used in the arsenate of lead-soap combination on the 
Ives variety at any time and that in applying the combination with 
Bordeaux to Concords and Catawbas the above factors influencing 
foliage injury should be kept in mind. The arsenate of lead-soap- 
lime mixture was safe wherever used, even on the Ives variety. The 
injury from spray materials appears to be cumulative from season 
to season. The combinations of spray materials and factors influ- 
encing grape foliage injury warrant further experimentation. 
Dusting for Control of Grape-Berry Moth. 
Much interest is centering in the application of insecticides and 
fungicides in dust form as compared with the liquid application. 
In an attempt to avoid all spray residue on grapes at harvest time, 
grape-dusting experiments were conducted in 1916, 1917, and 1918. 
The final infestation in check plats adjacent to the dusted plats was 
so light as to give inconclusive results except in 1916. The plan of 
the 1916 experiments and the results recorded are presented in 
Table IX. 
Table IX. — Dusting experiment for control of grape-berry moth, Sehonhardt 
Vineyard, Venice, Ohio, 1916. 
Dust and spray mixtures 
used and dilutions. 
Spray applica- 
tions. 
Counts of infested grapes at harvest, Oct. 13, 1916. 
Plat 
No. 
3 to 5 
days 
after 
grapes 
bloom, 
June 
29. 
When 
second- 
brood 
larvae 
begin to 
hatch, 
Aug. 4. 
Num- 
ber of 
vines 
exam- 
ined. 
Num- 
ber of 
clus- 
ters 
exam- 
ined. 
Num- 
ber of 
grapes 
exam- 
ined. 
Num- 
ber of 
clus- 
ters 
in- 
fested. 
Num- 
ber of 
grapes 
infest- 
ed. 
Per- 
cent- 
age of 
grapes 
in- 
fested. 
1 
Arsenate of lead powder, 2J 
pounds to 50 gallons; Bor- 
deaux, 3-3-50; laundry soap, 
2 pounds to 50 gallons. Li- 
X 
Dust mixture, arsenate of lead 
powder 10 per cent, hy- 
X 
X 
8 
6 
8 
211 
215 
239 
6,330 
6,450 
7,170 
211 
202 
239 
2,978 
1,194 
5,668 
47.04 
2 
3 
Arsenate of lead powder, 2£ 
pounds to 50 gallons; Bor- 
deaux, 3-3-50; laundry soap, 
2 pounds to 50 gallons 
x 
18.51 
79.05 
