60 
BULLETIN 903, U. S. DEPARTMENT OE AGRICULTURE. 
Some of the lower pots of the cages were filled with quartz of 
mixed grades. This was done chiefly for the purpose of experi- 
menting with liquid fertilizers as to the bearing of fertilizing 
substances upon the behavior of infested vines as an adjunct to 
similar vineyard experiments. Twelve out of 36 lower pots con- 
tained quartz. It was found that the wandering larvae were able 
to descend to rootlets growing in the quartz as easily as to those 
growing in earth. On the other hand, the phylloxera? were not able 
to exist on the larger roots in the quartz in appreciable numbers, 
as it appeared that they could not pass through the quartz when it 
was packed around the root. This is similar to the condition existing 
on very sandy soils, wherein the phylloxera? are unable to travel 
when the sand becomes packed around the roots. 
Table XIII indicates the incubation and development of the 
radicicoles on the roots of living vines. 
Table XIII. — Incubation and development of radicieole of the grape phylloxera 
on living vines, Walnut Creel; Calif., 1913-1915. 
FIRST GENERATION, 1913. 
Indi- 
vidual 
No. 
Date egg 
deposited. 
Date egg 
hatched. 
Incuba- 
tion 
period. 
Date 
insect 
matured. 
Growing 
period. 
Total 
period of 
develop- 
ment. 
Variety of vine and 
number of cage. 
Average 
temper- 
ature. 
Days. 
Bays. 
Bays. 
° F. 
1 
Apr. 29 
Mav 2S 
...do 
May 14 
June 6 
...do.... 
15 
9 
9 
June 8 
June 25 
...do 
25 
19 
19 
40 
28 
28 
Mission VTI 
60 
2 
do 
67 
3 
do 
67 
4 
...do.... 
...do.... 
9 
June 26 
20 
29 
do 
67 
5 
...do 
...do.... 
9 
June 2S 
22 
31 
do 
67 
6 
...do.... 
...do.... 
9 
June 29 
23 
32 
do 
67 
7 
...do 
...do.... 
9 
June 30 
24 
33 
do 
67 
8 
...do.... 
...do 
9 
...do.... 
24 
33 
do 
67 
9 
...do 
...do 
9 
...do.... 
24 
33 
do 
67 
10 
June 14 
June 22 
8 
July 5 
13 
21 
Burger VI 
69 
11 
...do 
...do 
8 
July 8 
16 
24 
do 
69 
12 
...do 
June 23 
9 
July 7 
14 
23 
do 
69 
13 
...dc... 
June 22 
8 
Julv 9 
17 
25 
do 
69 
14 
...do.... 
June 24 
10 
July 14 
20 
30 
do 
69 
15 
June 15 
...do.... 
9 
...do.... 
20 
29 
do 
69 
16 
...do.... 
...do.... 
9 
July 15 
21 
30 
do 
69 
17 
...do.... 
June 26 
11 
July IS 
22 
33 
do 
69 
18 
June 16 
...do.... 
10 
July 21 
25 
35 
do 
69 
19 
June 8 
June 17 
9 
July 9 
22 
31 
Burger V 
68 
20 
...do.... 
...do.... 
9 
...do 
22 
31 
68 
21 
...do 
June 19 
11 
July 13 
24 
35 
'".\'.Ao.V/SSS^V.".V.\'.'.\ 
69 
22 
...do.... 
...do 
11 
...do.... 
24 
35 
do 
69 
23 
...do 
June 20 
12 
July 15 
25 
37 
do 
69 
24 
...do.... 
June 17 
9 
July 7 
20 
29 
do 
68 
25 
...do 
...do.... 
9 
July 8 
21 
30 
do 
68 
26 
...do 
June 18 
10 
July 2 
14 
24 
do 
68 
27 
...do.... 
...do.... 
10 
...do.... 
14 
24 
do 
68 
28 
...do 
...do.... 
10 
...do 
14 
24 
do 
68 
29 
...do.... 
...do 
10 
July 4 
16 
26 
do : 
68 
30 
...do.... 
...do 
10 
Julv 6 
18 
28 
do 
68 
31 
...do 
...do 
10 
...do.... 
18 
28 
do 
68 
32 
...do.... 
...do 
10 
...do 
18 
28 
do 
68 
33 
...do 
...do 
10 
July 7 
19 
29 
do 
68 
34 
...do.... 
...do.... 
10 
...do.... 
19 
29 
do...-. 
68 
35 
May 25 
June 4 
10 
June 19 
15 
25 
do 
67 
36 
...do.... 
...do.... 
10 
June 21 
17 
27 
do 
67 
37 
...do.... 
June 5 
11 
June 23 
18 
29 
do 
67 
38 
...do 
...do.... 
11 
June 24 
19 
30 
do 
67 
39 
...do 
June 6 
12 
June 25 
19 
31 
do 
67 
40 
...do.... 
...do 
12 
...do.... 
19 
31 
do 
67 
41 
...do.... 
...do.... 
12 
June 27 
21 
33 
do 
67 
42 
...do 
...do 
12 
...do.... 
21 
33 
\'".'.6o.'.'.".'"".'.,\..." 
67 
43 
...do.... 
...do.... 
12 
June 29 
23 
35 
do 
68 
44 
...do.... 
June 8 
14 
Julv 2 
24 
38 
do 
68 
45 
...do.... 
...do.... 
14 
Julv 3 
25 
39 
do 
68 
