IOO 
Journal of Agricultural Research 
Vol. XXV", No. 2 
such translocation may be considered as a result of masking by the new 
environment, unless they are masked by new symptoms of a second 
disease. 
Tubers of a mosaic lot were divided and part of each tuber was planted 
in northeastern Maine and part in Colorado (45, p. 250). During the 
same season, mottling was distinct in the part in Maine and absent from 
the other. A similar lot was divided likewise and grown partly in north¬ 
eastern Maine and partly at Washington, D. C. (45, p. 250 ), and during 
the same season mottling was distinct in Maine but doubtfully ascer¬ 
tained in many hills at Washington. In three successive seasons a 
number of partly mosaic lots were divided and grown partly in north¬ 
eastern Maine and partly in southwestern Maine (45, p. 250). Usually 
the part of a lot grown in the southwestern area showed much less 
mottling than the other part, while the reverse never was noted. Re¬ 
covery of the mottled appearance followed the return of a part to the 
northeastern area. 
In 1922, a similar test on the effect of different climatic conditions on 
plants from the same tuber was conducted with 30 Bliss Triumph tubers 
and with an equal number of Green Mountain tubers apparently having 
mild mosaic. A seed piece from the same tuber was planted in each of 
these localities: Presque Isle, Me.; Riverhead, Long Island, N. Y.; and 
Norfolk, Va. Observations were made by the same person, one of the 
writers, in the three localities. The results of these observations indi¬ 
cated that mottling was less distinct on the foliage at Norfolk than in 
the other localities. It was also noted that most of the vines in the 
three localities showed mild mosaic symptoms; a few plants plainly dis¬ 
closed mosaic-dwarf or bad mosaic symptoms. However, mosaic- 
dwarf appeared on the plants from the same tuber in each of the three 
localities and no tuber produced plants having mild mosaic in one locality 
and a different stage of mosaic in another locality. It appears that 
the difference in climatic conditions here as in the preceding tests chiefly 
produced a difference in the distinctness of the mottling, the stage or 
type of mosaic remaining the same. 
Progeny of Green Mountain curly dwarf hills were grown partly in a 
warm room (approximately 67° F. or 19 0 C.) in the Orono greenhouse in 
1919-20, and partly in a cool room (approximately 56° F. or 13 0 C.). 
Mottling appeared, was mostly restricted to the tissues along the veins, 
and was so restricted more in the warm room. The same was true of 
progeny of mosaic hills selected in the same lot. Such a hill grown in the 
open is shown in Plate 15, A. 
In 1919 a stock of Green Mountains with about 80 per cent mosaic 
was grown on a number of fertilizer plots. Both the percentage of mosaic 
plants and the distinctness of mottling in those mosaic were reduced 
somewhat during the first part of the season by high-nitrogen and high- 
potash fertilizers. 
In 1919 four mosaic tubers were split in two and one-half of each was 
planted under an insect cage in the field and the other in the open. In 
two cases the caged hills were more distinctly mottled than the corre¬ 
sponding uncaged ones. 
Twelve tubers from Bliss Triumph mosaic hills were grown in the 
Orono greenhouse in 1920-21. They were split in two, and one half of 
each was planted in a warm place (approximately 75 0 F. or 24 0 C. mean 
temperature) and the other half in a cool place (approximately 6o° F. 
or 16° C. mean temperature). Wrinkling and mottling were more marked 
