190 
F. T. Brooks . 
June, July, and August, examining potato fields in detail, under the 
general direction of Professor Oliver and the writer, the latter being 
then Plant Pathologist to the Food Production Department of the 
Board of Agriculture. As the exigencies of the war prevented the 
continued presence of the same observers throughout this period, 
continuity was maintained by relays of workers. 
The plan of operations was as follows: 
The observers were divided into three groups stationed in 
different parts of the island. At each centre two series of 
observations were carried out; 
(a) By rapid examination of a considerable number of 
potato fields scattered in the neighbourhood. 
(b) By intensive inspection of each individual plant in 
small plots. 
If any of the plots under rapid survey became suspiciously 
affected, it was the intention to place them under detailed observa¬ 
tion. Plots of early and second early varieties were usually chosen 
for this work as it is well known that these are usually affected by 
blight before the later varieties. 
The mode of procedure in the detailed inspection .was as 
follows :—each plant was minutely examined, as far as possible 
from day to day, and any discolouration in the haulm that came 
under suspicion of being an early stage in the development of blight 
was noted, and the plant marked for further observation. Some¬ 
times the affected part was removed and incubated under condi¬ 
tions suitable for the development of Phytophthora and then 
examined microscopically in a room near the plots, temporarily 
used as a laboratory. Dark patches on the stem and lower leaves 
were the symptoms especially looked for. 
Unfortunately two of the centres had to be closed before 
Phytophthora appeared and it is not worth while to describe the 
negative evidence alone obtained at these centres. At the third 
centre the potato fields under rapid observation gave only negative 
results but Phytophthora appeared in two of the plots under detailed 
examination and a summary account of these results will now be 
given. Many of the following notes are based upon observations 
made by Mr. H. Stansfield by whom also the plans of the plots 
were drawn. 
PLOT 7. 
This plot, situated at Haven Street, contained about 130 plants 
of the second-early variety, White Beauty of Hebron, grown from 
own-saved seed. In 1917 the crop was onions and two years 
previously the ground was a fowl run, All these plants were of 
