I70 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
supplies in the Lea Valley by carefully filtering large volumes of 
water. Our results showed that deep artesian wells were free from 
contamination, but shallow wells, brooks, and ponds were frequently 
polluted with fungal and bacterial parasites. 
While sterilization of the propagating soil is extensively practised 
by the more advanced growers, there are those who do not find it 
convenient to adopt such methods, and who desire some fungicide 
which may be applied to the soil round the growing plant and which 
will destroy the fungus without injuring the plant. As the result of 
investigation at Cheshunt, such a compound has been devised and 
has proved highly satisfactory in the Lea Valley. For convenience 
it has been named " Cheshunt Compound." Finely ground copper 
sulphate and fresh ammonium carbonate are intimately mixed in 
the proportions of two parts by weight of the former and eleven parts 
of the latter. The mixture should be stored in a tightly stoppered jar 
for forty-eight hours, after which the solution is prepared by dissolving 
J oz. of the mixture in 1 gallon of water. The solution may be applied 
to the seed-boxes, pots, or ground in which plants are growing, and will 
destroy the fungal parasites without injuring the plants. It must 
be understood, however, that plants which have been already 
attacked will receive no benefit from the solution, but will eventually 
die. They may be saved only by cutting off the tops above the 
diseased part and treating as cuttings. 
The next disease of importance attacks the bottom truss at a time 
when it is commencing to ripen, and is known as " Buck-eye Rot " 
or " Black Rot." The lesions take the form of brown and grey 
patches with darker brown concentric rings, and somewhat resemble 
the eye of a large animal. 
The disease is caused by a fungus, Phytophthora terrestria Sher- 
bakoff = Ph. parasitica Dastur. The disease organisms are splashed 
up from the soil in the process of watering, and are held in a film of 
water between the fruits of the bottom trusses. 
Here the conditions are very suitable for infection, and the fungus 
readily penetrates into the fruit. In nurseries where this disease 
occurs it is advisable to mulch early and so prevent the .disease 
organisms from being splashed on to the plants. For this purpose a 
straw mulch is eminently suitable. The rapid progress of the disease 
is to a large measure due to the ideal conditions of humidity which 
prevail round the base of the plant, and careful attention to tem- 
perature and ventilation will do much to check the disease, by keep- 
ing the bottom truss and leaves as dry as possible. Diseased fruits 
must be removed immediately, for the fungus spreads along the 
branches of the truss back into the main stem, where it soon causes 
the death of the entire plant. 
Later in the season " Stripe Disease " * and " Sleepy Disease " f 
* For a more detailed account of this disease see Annals of Applied Biology, 
vol. vi. Nos. 2 and 3, Dec. 191 9. 
■j- For a more detailed account of this disease see Annals of Applied Biology, 
vol. ix. No. 2, 1922. 
