26 
BULLETIN 550^ T. S. DEPARTMENT .OF AGPJCULTTJBE. 
A/o/?r/? 
very poor adhesive. Arsenate of lead at the rate of 2 J pounds 
(powder) to 50 gallons of liquid (Plat II) appeared to be little more 
effective at the increased strength than when used at the rate of 1J 
pounds to 50 gallons (Plat I). 
Plats where the first application was made with "set nozzles" 
(Plat IV) and where it was omitted altogether (Plat V) showed a 
fairly satisfactory reduction of infestation. It should be noted that 
the infestation in the cheeks in these two plats was not as heavy as 
that in the checks adjacent to 
Plats I, II, and III. 
EXPERIMENT IN THE PHILLIPS VINEYARD, 
NORTH EAST, PA., 1916. 
This vineyard consisted of Ni- 
agara grapes, whereas in all other 
vineyards in which experimental 
spraying was done the grapes were 
Concords. It covered about two 
acres, irregular in shape, and was 
divided into two plats. To guard 
against natural irregularities of 
left in each of the three corners, 
in the diagram (fig. 9). 
ms^&t 
/F^ST 
Fig. 9.— Diagram, showing the arrangement of ex- 
perimental plats in the vineyard of Mr. M. D. 
Phillips, North East, Pa., 1916. The sprayed plats 
are marked with Eoman numerals and the check 
plats with letters. (Original.) 
infestation unsprayed checks were 
The arrangement of plats is shown 
Table 18. — Spray mixtures used and methods and dates of application, Phillips vine- 
yard, North East, Pa., 1916. 
Arsenate 
of lead 
(paste). 
Bordeaux mixture. 
Laundry 
soap. 
Water. 
Method of 
application. 
Plat Xo. Dates sprayed. 
Lime. 
Copper 
sulphate. 
I July 5 and 22.. 
II July 5 and 22.. 
Pounds. 
5 
3 
Pounds. 
3 
3 
Pounds. 
3 
3 
Pounds. 
1 
1 
Gallons. 
50 
50 
"Trailers." 
Do. 
Table 19. — Percentage of infestation in experimental plats. Phillips vineyard, Xorth 
East, Pa., 1916. 
Number 
of 
clusters. 
Total 
berries. 
First brood. 
Second brood. 
Plat Xo. 
Infested 
berries. 
Infesta- 
tion. 
Infested 
berries. 
Infesta- 
tion. 
i 
400 
400 
200 
200 
200 
15, 200 
16, 000 
7,200 
7,600 
8,000 
436 
107 
423 
1,186 
2S9 
Per cent. 
2.87 
.67 
5.88 
15.61 
3.11 
479 
142 
5,135 
6,114 
4,034 
Per cent. 
3.15 
II 
.89 
Check A 
71.32 
Check B 
80.45 
Check C 
50.43 
