Mar., 1923] CLAYTON — SOIL MOISTURE AND FUSARIUM WILT 
137 
Infection was secured at medium and low moistures, but none at sat¬ 
uration. 
Experiment II was carried on the following fall; in this case the temper¬ 
ature conditions maintained were favorable for a maximum development 
of the disease. The regulation of moisture was not entirely satisfactory 
and the methods of planting and handling the crocks were not yet perfected. 
The results of this experiment, however, showed decisively that plants 
grown in saturated soils do not develop the wilt. With high moisture 
content which did not quite reach saturation (30-35 percent), the wilt 
developed, and the same was true with medium moisture content (25-30 
percent). There was a distinct falling off in the amount of disease in soils 
which were dry enough (22 percent and below) markedly to check growth. 
The results from this series are summarized in table 1. 
Table i 
Soil Moisture, 
Percent 
No. 
Plants 
Percent 
Healthy 
Percent 
Diseased 
Percent 
Dead 
18-25. 
19 
47 
3 i 
22 
26-27. 
27 
15 
59 
26 
40 (saturation). 
12 
100 
00 
00 
Experiment III . This experiment was begun December 22, 1919, and 
completed March 1, 1920. The soil was steam-sterilized and inoculated 
with a spore suspension of Fusarium lycopersici. One-gallon crocks were 
filled, planted, and carried into a cool temperature (i5°-20° C.) greenhouse. 
Here the plants grew for a period of four weeks, with an air temperature of 
15° to 20° C. and a soil temperature averaging about one degree less. There 
was no development of the disease at these temperatures. 
On January 19, 1920, a series of crocks containing inoculated plants 
was carried into a temperature favoring the disease (about 28° C.), the 
soil having previously been adjusted to various moisture contents. 
On February 20 the condition of the plants was as shown in table 2. 
Table 2 
Moisture, Percent 
No. Plants 
No. Diseased 
No. Dead 
14-16. 
4 
0 
0 
16-18. 
4 
3 
1 
23-24. 
4 
4 
3 
26-28.. 
4 
3 
2 
31-33 . 
4 
4 
4 
35 (saturation). 
2 
0 
0 
On March 1 the experiment was discontinued and the data taken are 
shown in table 3. 
Experiment IV. The tomatoes used were planted December 22, 1919, 
and grown at the low temperature (i5°-20° C.) until February 9, 1920. 
