24 BULLETIN" 837, U. S. DEPARTMENT OF AGRICULTURE. 
greater than where arsenate of calcium was used alone and less 
than where arsenate of lead was used alone. 
Summary of Results with Spray Materials. 
Arsenicals. — Arsenate of lead powder at the rate of 1J pounds to 
50 gallons proved adequate for commercial control of the grape-berry 
moth in the average case. Arsenate of calcium proved almost 
equally as efficient as arsenate of lead when compared on the basis 
of arsenical content and has the additional advantage of leaving less 
residue at harvest time. 
Spreaders and adhesives. — Resin fish-oil soap at the rate of 1 
pound to 50 gallons possessed all the qualities desired and required 
33 per cent less spray material than laundry soap and 86 per cent 
less than soft soap, to wet the grape clusters on an equal area of 
vineyard. 
Spray combinations. — The mixture of arsenate of lead and soap 
with Bordeaux should be used with care on Catawba and Concord 
varieties. The Bordeaux mixture should be omitted on the Ives va- 
riety. Stone lime at the rate of 2 pounds to 50 gallons should be 
added to the arsenate of lead-soap combination when Bordeaux 
mixture is omitted. 
Dust mixtures. — The dust mixture of arsenate of lead and hy- 
drated lime did not adhere to the grape clusters as well as the liquid 
sprays. ' The dust material was only partially effective for the con- 
trol of the grape-berry moth. 
Spray residues. — Objectionable residues do not result when the 
first and second spray applications are used with care. A spray ap- 
plication in August with the materials necessary for benr-moth 
control will leave a residue which will bar the fruit from the basket 
market. 
COST OF TRAILER SPRAYING. 
Because of the fan training system it was necessary, when spray- 
ing, to drive between each two rows of grapes. Each rodman sprayed 
but one side of one row at a time. In the Chautauqua-Erie belt it 
was found possible for a man to spray both sides of a row as he went, 
but there appears to be little gain in time by the latter method. In 
all of the experimental work it was found possible to mix and apply 
6 tank loads of 150 gallons each or a total of 900 gallons in 9 work- 
ing hours. This amount of material covered from 3 to 8 acres, de- 
pending on local conditions, and averaged about 5 acres. About one- 
half more material was required for the second application than 
for the first. Where the third application was made on plats that 
had received the second, the amount was about the same as for the 
