114 DISEASES OF GLASSHOUSE PLANTS 
fruit may be recognized by the appearance of discoloured 
patches, varying from grey to reddish-brown in colour, 
frequently arranged in alternating zones of colour so 
that the whole lesion resembles the eye of a large animal 
(Fig. 33). Thus the term “ buckeye rot” aptly describes 
the appearance of the disease. 
The main cause of the disease is a fungus, Phytoph- 
thora parasitica Dastur., which is synonymous with 
Ph. terrestria Sherbakoff, but occasionally Ph. cryptogea 
Pethybridge and Lafferty has been found as the cause. 
Fruits become infected by touching the soil in which 
the disease organisms live, or, on the other hand, careless 
watering may splash infected particles of soil on to the 
truss as it hangs near the ground. The infection is held 
in a film of water between the fruits, and readily attacks 
them. The cold, moist conditions operative in the 
neighbourhood of the bottom trusses are especially | 
favourable to this disease, and if the fruit becomes 
infected the disease makes rapid progress and spreads 
from fruit to fruit through the entire truss. Finally 
the fungus may work back along the truss and attack 
the main stem, when the entire plant dies rapidly. The 
diseased fruits remain quite hard and firm except when 
bacteria are present, when a soft watery rot ensues. 
Under moist conditions the fungus grows out into the 
air and the fruits become covered with a dense white 
fungal growth. Innumerable spores are produced and 
the infection spreads rapidly in the process of watering. 
The disease may be prevented by early mulching 
with straw to cover up the infection and prevent it being 
splashed on to the fruit. In this respect, however, 
the mulch must not be applied until the soil has become 
properly warmed, as the mulch, placed over cold soil, 
prevents it from becoming warm, and so the rate of growth 
of the plant is much reduced. Where the disease has 
been abundant in previous years the soil may be watered 
after planting with a solution of ‘‘ Cheshunt Compound,” 
applied at the rate of four to eight pints per square yard. 
