70 DISEASES OF GLASSHOUSE PLANTS 
is only brown in colour, and somewhat darker than when 
infected by Verticillium or Fusarium. 
Infection takes place in June and July when the soil 
temperature is high. At this time, although the fungus 
is present in the roots, a well-grown plant may 
show no signs of disease, but after it has produced 
five or six trusses of fruit, and is consequently reduced 
in vigour, signs of root trouble appear. Thus, unless 
the conditions are exceptional, the outward signs of the 
disease do not appear earlier than the middle of August. 
Considerable financial losses, however, are incurred 
through the disease, which prevents the plants from 
continuing to bear fruit to the end of the season and 
causes their premature death. It has been calculated 
that between twenty and twenty-five per cent of the 
total yield per plant is lost when it is attacked by this 
fungus. 
Causal Organism.—The disease is caused by a 
fungus Colletotrichum tabificum Pethybridge. The actual 
hyphe are difficult to distinguish on the plant, and 
occasionally very small spores or conidia are produced. 
Typical resting bodies or sclerotia are formed, which 
are at first white in colour, but finally turn dark brown 
or black and become covered with dark brown bristles 
or setx, The fungus ramifies through the wood, and 
produces sclerotia inside the large wood vessels, and in 
any hollows inside the stem. Generally sclerotia are not 
produced until the plant is almost dead. 
Control.—The disease organisms develop most rapidly 
in soils rich in organic matter, and thrive in manure 
heaps and any straw or woody material. In the labora- 
tory the fungus has been cultivated successfully on wood 
and straw. It is thus obvious that clean cultivation by 
removing such materials is an important factor in the 
control of the disease. 
Watering the soil round the plant roots with a solution 
of ‘‘ Cheshunt Compound” has been found to prevent 
the disease from spreading. Sterilization with steam or 
