198 
F. T. Brooks. 
usually enriched with heavy dressings of farmyard manure and 
sea-weed. Potatoes are frequently grown on the same land year 
after year and as soon as the tubers are lifted in May and June, 
broccoli are planted. These early potatoes are grown very closely 
together, the rows being only about 10 inches apart and the seed 
sets 8 inches from one another. The plants are not earthed up as 
is the custom in most parts of the country. Successive visits were 
paid to the neighbourhood and the following is a record of the 
observations which are given as recorded on the spot. 
May 27. At this date the lifting of early varieties had already 
commenced. Blight was found in a field of the variety Sharp’s 
Express near Newlyn. The seed sets, which were obtained from 
Lincolnshire, had been sprouted and cut prior to planting during the 
third week of March. Before May 27th the weather had been dry with 
the exception of an occasional sea fog. In this field there were two 
areas on the sheltered side of a high hedge, each about a yard 
across, in which every plant was more or less attacked by blight in 
sporing condition, but in neither area could the disease be traced 
downwards to parts of the stems below soil level. In these two spots 
all parts of the plants above ground were attacked, including the 
flower buds, the stems often appearing to be invaded by way of the 
axils of the lower leaves. The fungus was fructifying on the laminae of 
the leaves, but suspected discoloured portions of petioles and stems 
also developed Phytophthora spores after incubation. In addition 
to these two areas, there were a few scattered spots of blight on 
the upper leaves in other parts of this and other fields close at 
hand. These had presumably arisen by secondary infection, 
probably from spores found in the two areas referred to. As 
regards this particular place there could be no doubt that blight 
first developed in these two well defined spots in the field. 
May 31. The same field was visited again. Blight had 
spread very little since the last visit, the weather having been dry. 
Another centre of infection was found, however, every plant within 
a circular zone two yards across being attacked, especially in the 
lower leaves and the parts of the stem just above soil level. As 
before, the disease could not be traced downwards to parts of the 
stems below soil level. 
Two other cerrtres of infection were found in two other fields 
in the same locality showing the same appearances as already 
described. In one of these the site was relatively dry, being 
situated on a slope with a southerly aspect. 
Many other fields of early potatoes in this vicinity were found 
to be free from blight. 
