CONTROL OF GRAPE-BERRY MOTH. 23 
The dust materials were applied with a small hand duster and 
the liquids with a gasoline power sprayer. In each case the appli- 
cation was made from either side of each row and a thorough cover- 
ing of foliage and fruit effected. The dust materials adhered to the 
grape foliage fairly satisfactorily but did not adhere well to the 
smooth surface of the grape berries. No rain fell from the time of 
the application until August 11 when a light shower occurred. 
When the vines were examined on August 19 only a trace of the 
dust material was in evidence on the foliage or fruit, while the 
sprayed fruit was well covered with spray material. It required 40 
pounds of dust material to dust 46 thrifty Catawba vines. At this 
rate and with the vines set 900 to the acre as is the practice in this 
section, it would require 783 pounds of material per acre. No doubt 
this would be materially reduced if a power machine were used 
for the dusting. If but half as much material were required per 
acre the amount of arsenical would be from 6 to T times as great 
as when applied in liquid form at the rate of \\ pounds of arsenate 
of lead powder to 50 gallons of spray and the liquid applied at the 
rate of 200 gallons per acre. The writers feel that the dust would 
have to be applied much more frequently than the liquid to be ef- 
fective for berry moth control. This method of application might 
be satisfactory for treating small home grape arbors when applied 
frequently. 
Speay Residue on Geapes at Harvest Time. 
Throughout these investigations records were kept on the com- 
parative amounts of spray residue on the grapes at harvest time. 
In all cases where the spray application shown as the third (fig. 1) 
was used in early August the fruit was heavily coated with spray 
material at harvest time. In nearly all cases where the combination 
of first and second sprays was used, and spraying completed by 
July 25, there was not sufficient spray residue at harvest time to 
affect the marketing of the grapes in baskets for table use. When 
either the first or second application was used alone the residue was 
lighter than when both were used. Slightly more residue resulted 
on the plats sprayed with arsenate of lead at the rate of 2J pounds 
than on those sprayed with the same material at the rate of 1J 
pounds to 50 gallons. No difference could be seen between the fruit 
from plats on which Bordeaux was included and those on which 
lime, 2 pounds to 50 gallons, was substituted for it. Slightly less 
residue was present on the plats sprayed with arsenate of calcium 
than on those sprayed with arsenate of lead where the comparison of 
material was on the basis of arsenical content. In one plat where 
these materials were mixed in the proportion of arsenate of calcium 
9 ounces to arsenate of lead 5 ounces, the amount of residue was 
