Aug. ix. 1923 Irish Potato Foliage Degeneration Diseases 257 
growth of the shoots from the diseased as compared with those from 
the healthy tubers were observably unlike. Slower growth occurred 
and a pinched, unhealthy and slightly abnormal appearance characterized 
the sprouts from tubers seriously affected with either mosaic or leaf roll. 
Plate 1, A (two potted plants and sprouted seed pieces from the same 
corresponding tubers), illustrates this point. The plant at the left ex¬ 
hibits extreme mosaic symptoms and the sprouts of the seed piece dis¬ 
tinct retardation in growth; the plant at the right, mild mosaic symp¬ 
toms and a nearly normal sprout on the seed piece. Plate 1, B, shows 
another case of retarded sprouting, the potted plant being from the same 
tuber as the sprouted seed piece and exhibiting extreme mosaic symp¬ 
toms. The plants shown in Plate 1, B, were from a parentage described 
as “healthy but adjacent to mosaic hills.’’ Plate 1, A, shows an addi¬ 
tional evidence of weakness and degeneration in the brown lesions on 
the several sprouts of the seed piece at the left. Schultz and Folsom 
(11, p. 321) have reported a “ spotting and streaking of the leaves, petioles 
and stems” apparently somewhat similar to the foregoing, accompanying 
mosaic symptoms induced in potato plants by artificial inoculation. 
RELATION OF MOSAIC AND LEAFROLL IN VERMONT 
Schultz and Folsom (12, p. 75) note that in northeastern Maine the 
Irish Cobbler is the only variety which shows more than a trace of leafroll 
in commercial fields and that it “seldom shows more than a trace of 
mosaic, while the Green Mountain and Bliss Triumph varieties are seldom 
found with only a trace of mosaic.” 
In Vermont the facts with reference to these points are somewhat 
different. As in Maine, Irish Cobblers are more subject to leafroll than 
to mosaic, but this variety in Vermont frequently shows more than a 
“trace of mosaic.” Further, Green Mountains in Vermont are now 
quite as commonly, though in general not as seriously, affected with 
leafroll as with mosaic. The State certified seed-potato inspectors during 
the past two or three seasons have found fields with relatively high 
percentages of mosaic much more frequently than fields with high per¬ 
centages of leafroll. It is also a common experience now in this State 
to find in many stocks of Green Mountains, and less frequently in Irish 
Cobblers, both mosaic and leafroll infection in the same field. The 
percentages of mosaic found are frequently reported as “only a trace.” 
In these respects the conditions in Vermont with reference to mosaic 
and leafroll occurrence are appreciably different from those in Maine. 
SIMULTANEOUS OCCURRENCE OF MOSAIC AND LEAFROLL IN THE SAME 
PLANTS 
Stewart ( 13) in 1916, in recording his observations on “some degen¬ 
erate strains of potatoes,” reports that “certain hills were much affected 
with leafroll and showed also traces of mosaic.” In studying the symp¬ 
toms of mosaic and leafroll plants both in the field and in the greenhouse, 
it has frequently been observed by the writer that a plant may exhibit 
the characteristics of both diseases at the same time. Instances of this 
have been noted both in the early part of the season and later. When 
the symptoms appeared very early it was obvious that the double infec¬ 
tion had been carried in the seed tuber, while later appearances might 
have been due to secondary infections of one or both diseases. In 
most cases where this double infection was observed, the unhealthy 
