STEM NEMATODE ON WILD HOSTS. 5 
found in cultivated strawberries in northwestern Oregon or in Wash- 
ington. 
Quite frequently a large association of plants was found with 
the Fragaria or Hypochaeris, including the salal (Gaulthemt 
shollon). the brake (Pteris aquilin-a), a moss, and a large number 
of small herbaceous flowering plants. All of these plants were care- 
fully examined without finding any sign of the disease. 
RELATION TO ENVIRONMENT. 
In the case of Fragaria, nearness to the ocean appeared to be a 
factor which influenced infection. In most cases no diser.se was 
found 100 yards from the shore, even though it was abundant at 
the edge of vegetation above the beach. Quite frequently this 
host growing in the sand about the driftwood was affected. Again, 
frequently the sea side of a sand dune would have affected plants, 
while those, on the land side would be free. Slopes near a rocky 
promontory upon which the waves dashed at high tide were often 
heavily infested. This was the case at Seal Rocks, in Lincoln 
County, at which point wild-strawberry patches quite extensive in 
area on a bluff 50 feet high were found more than 50 per cent 
affected with the nematode disease. (PL III, B). At Yaquina 
Head (PI. Ill, A), where meadow grasses and strawberries pre- 
dominate, the disease was found in great abundance, especially on 
the steep north slope of the hill. Over the entire slope from the 
beach to the summit, probably 500 feet high, diseased plants were 
found. Plate III, (7, shows a view of a typical spot on the hillside 
where the disease was found. 
A similar condition of a high percentage of diseased plants in 
strawberry meadows near the shore existed at another promontory 
known as " Jump-off Joe.*' Diseased plants occur close to the beach 
and on the side of the bluff to the very top. None was found, how- 
ever, back of the edge of the bluff, a distance of 50 feet. 
.In many cases it appeared that almost constant high humidity 
was required to maintain infection and favor the spread of the 
disease on this host. This was obviously obtained at times by actual 
salt spray from the ocean and again from the heavy fog that occurs 
so frequently near the coast. When the photograph reproduced in 
Plate III, B, was taken, the atmosphere was saturated by a falling 
mist that nearly shut the distant rocks from view. 
Nearness to the ocean did not appear to be a factor in the case 
of Hypochaeris. At Newport, where the plant grew abundantly as 
a weed in meadows, on lawns, and beside the streets, the disease 
was found for several hundred yards back into the town. It also 
occurred some distance from the shore in Tillamook County, Oreg., 
and near Long Beach, Wash. The presence of the infested Hypo- 
chaeris plants a considerable distance from the shore led to the search 
for and discovery of the disease at the inland valley points, where 
direct influence of ocean moisture could be no factor in infection. 
ORIGIN AND DISSEMINATION OF THE DISEASE. 
The possibility of the infection of the wild-strawberry plants 
having originated in the cultivated fields was at first considered 
