110 
BULLETIN 903, U. S. DEPARTMENT OF AGRICULTURE. 
Table XXXV. — Field experiments on inoculation of vines by wandering larvce 
of the grape phylloxera, Walnut Creek, Calif., 1915. 
No. of 
vine. 
19 
10 
11 
12 
13 
114 
15 
116 
17 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
128 
29 
30 
31 
32 
33 
Type of soil in can. 
Variety of 
vine. 
Date of 
planting 
can in 
vineyard. 
Date of 
taking up 
can in 
vineyard 
Distance | 
of vine in 
can from 
trunk of 
infested 
vine in 
vineyard. 
Result. 
Silt loam. 
do... 
do... 
do... 
do... 
....do 
....do 
Heavy black loam 
do 
....do 
Heavy black clay 
....do 
....do 
Sandv silt 
....do 
....do 
Pure sand 
Heavy black clay 
Sandy silt 
Heavy black loam 
Heavy black loam 
Heavy black clay 
Sandy silt 
Heavy black loam 
....do 
Heavy black loam 
do 
Pure sand 
Sandv loam 
do 
Heavy black loam 
Heavy black clay 
Sandv silt 
,2 parts; silt, 1 part 
loam 
loam. 
, 2 parts; silt, 1 part 
, lpart; silt, 1 part. 
loam 
,2parts; silt, lpart 
lpart; silt, i part. 
, lpart; silt, lpart. 
loam 
Mission 
•Zinfandel. . 
Carignan — 
Zinfandel. . 
Carignan. . 
Zinfandel. 
►Carignan.. 
Zinfandel... 
July 14 
..do.. . 
..do... 
July 15 
..do 
Julv 17 
..do... 
..do... 
[Julv 20 
..do... 
July 21 
..do... 
..do... 
Julv 22 
..do... 
..do... 
..do... 
July 24 
..do 
..do... 
..do... 
..do... 
..do... 
/..do... 
\July 27 
'..do... 
..do... 
..do... 
..do... 
..do... 
July 29 
..do... 
..do... 
Sept. 
Sept. 
Sept. 
Sept. 
Sept.' 
Sept. 
Sept. 
s t: 
Sept. 
Sept. 
Sept. 
..do. 
Sept. 
Sept. 
..do. 
..do. 
..do. 
..do. 
Sept. 
..do. 
Sept. 
..do. 
s t: 
..do. 
..do. 
..do. 
..do. 
..do. 
..do. 
..do. 
Feet. 
•Uninfested. 
Infested. 
•Uninfested. 
■Infested. 
Uninfested. 
i Entire vines died shortly after having been planted in vineyard, therefore can not be included in 
results of experiment. 
Of the 27 vines which were alive when the cans were taken up, 21 
had been planted in the ph}dloxera " spot " on light soil and 6 in 
phylloxera " spots " on heavy black clay. None of the latter and only 
4 of the former group became infested. Vine 6 was examined 
September 9, and an infestation consisting of 1 adult radicicole 
and about 12 larvae was found. This indicated that a single wan- 
derer had established itself on the vine. On vine 11, on the same 
date, there were found 3 adults and about 20 larvae. On vine 12 
on September IT there were 6 adults and about 200 larvae, besides 
many eggs. On vine 13 on September 15 there were over 350 phyl- 
loxerse, including some 50 adults. Vines 11, 12, and 13 were planted 
around the same infested vine. In the case of vine 13 the infestation 
was started either by a large number of wandering larvae in August 
or more likely by one or two wanderers directly after the vine was 
planted on July 21. Since in August the phylloxera generation 
cycle may be passed in less than 22 days, and since each mature 
radicicole may average 8 eggs per diem for several weeks, it would 
have been possible for the infestation on vine 13 to have developed 
