DISEASES DUE TO FUNGI 77 
throughout the year except for such alteration as was 
caused by seasonal variation. The results given in 
Table 3 (p. 76) indicate that the conditions during the 
months of June, July, and August are unfavourable to 
the rapid progress of the fungus in the plant. 
These results indicate the probability that tempera- 
ture is an important factor in relation to the disease. 
As a series of glasshouses where different temperatures 
could be constantly maintained was not available, 
inoculated plants (hypocotyl stab) were placed in different 
TABLE 4. 
House. House. 
| Tomato Cucumber 
Average temperature °C. | 12-5° | 16-6° 20-0° 25° 
Absolute minimum ° C. 5-6 11-1 12-2 20-6 
Absolute maximum ° C. 20-6 22-2 27°8 33:3 
Date of inoculation 14/4/20 | 14/4/20 | 14/4/20 | 14/4/20 
No. of days after inocula- 
mon... Ae “P 21 21 21 21 
Ratio of wilted to total 
leaves .. “s = 0:10 6:12 8:12 0:12 
Height of discoloured 
wood above stab... | 15cm. | 26cm. | 28cm. | 9 cm. 
No. of days from inocula- 
tion to complete wilt 49 28 28 No wilt 
after 
80 days 
positions in the experimental houses, corridors, etc., 
under different average temperature conditions. Twelve 
plants were placed in each position, and the average 
temperatures were calculated from readings taken twice 
daily from maximum and minimum thermometers placed 
beside the plants. The final observations, shown in the 
Tables 4 to 7, were taken twenty-one days after 
inoculation, and where figures are given they represent 
the average obtained from twelve plants. 
While the results obtained are open to criticism 
because of the wide range of temperature to which the 
