76 DISEASES OF GLASSHOUSE PLANTS 
of which the fungus tides over the winter or other adverse 
conditions. Such sclerotia may be produced in the dead 
remains of a diseased plant, or generally in the soil 
humus. In the spring, the sclerotia germinate and pro- 
duce hyphe able to infect young healthy plants. Suscepti- 
bility to the disease is influenced by the character of the 
plant, as indicated in Table 2 (p. 75), giving the results 
of inoculating plants in different stages of growth and of 
varying degrees of hardness and softness of growth. 
It is a general experience with most diseases that 
plants developing rapidly and producing quantities of 
soft, sappy growth are the most susceptible to disease, 
but in this case the above table indicates the reverse 
effect, for plants of “ hard” growth with a thin stem, or 
plants obviously starved, most readily succumb to the 
disease. 
TABLE 3. 
f Days after 
ee oa Tnoeuletign ba a soph Pathological Symptoms. 
27/3/19 15 Complete wilt with slight 
yellowing 
26/4/19 14 Complete wilt, no yellowing 
25/5/19 10 Do do 
; 27/6/19 No wilt in 10 weeks | Lowest 9 leaves turned 
yellow and _ partially 
dried up. 
25/7/19 Do. do | Lowest 3 leaves desiccated 
25/8/19 53 Complete desiccation of 
leaves from base upwards 
22/9/19 40 Bottom 4 leaves desiccated 
22/10/19 26 Complete wilt with practi- 
cally no yellowing 
Temperature Relations.—If different sets of tomato 
plants are inoculated with V. albo-atrum each month 
throughout the year, striking results are obtained. In 
such an experiment twelve tomato plants were inoculated 
each month, and were grown under similar conditions 
