152 TWENTY-FIFTH ANNIVERSARY REPORT. 
Other potato diseases studied more or less are the following: 
(1) An internal browning of potato tubers'®® observed on Long 
Island in 1895. ‘Tubers, outwardly perfect, show, within, numerous 
brown spots scattered irregularly through the flesh. The cause was 
not determined. 
(2) A stem blight or wilt disease often destructive on Long 
Island The leaves at the tips of the shoots roll up, turn yellow 
or purplish, then the entire plant wilts and dies. The tubers appear 
sound, but when cut at the stem end blackened fibers are seen pene- 
trating the flesh to a considerable distance. Affected tubers do not 
rot. The seat. of the trouble is plainly in the stem just below the 
surface of the soil where it first becomes discolored then dry and 
shriveled. Apparently, the disease is not transmitted with the 
seed.1°° The cause was not determined. We can not agree with 
Dr. Erwin Smith?®! who has expressed the opinion that this disease 
is caused by the potato dry-rot fungus, Fusarium oxysporum. 
(3) Pimply potatoes caused by the larvae of the flea beetle boring 
into the growing tubers. Previous to this time the feeding habits 
of flea-beetle larvee were unknown. 
(4) A new, but unimportant, Fusarium disease of potato stems.2 
(5) Rhizoctonia on potato tubers and stems.16# 
QUINCE. 
No extended investigation of any quince disease has been carried 
out at the Station. However, at various times, some observations 
and notes have been made. 
In the investigation of the fire blight disease of the pear, re- 
viewed on a previous page, it was shown by means of cross-inocula- 
tion experiments that the fire blight of quince and apple twigs is 
due to the same cause, namely, to bacteria. And in the investiga- 
tion of apple canker (page 122) the quince was taken into con- 
sideration because of its close relationship to the apple. It was 
found that the apple canker fungus, Spheropsis malorum, is capable 
of attacking also living quince branches. That Spheropsis may 
— 
*$ Bul. 101:78-83 (1896) ; same in Rpt. 15:504—-500. 
*™ Bul. 1or:83-84. 
Bul. 138:632-634 (1897); in Rpt. 16:421-423. 
7 UJ. S. Dept. Agr. Bur. Plant Indus. Bul. 55:10 (1904). 
7 Bul. 101:84-85; Bul. 113 (1806) (same in Rpt. 15:513-519). 
= Buleetor:8s: 
*#" Bul. 186:17-22 (1901); same in Rpt. 19:110-113. 
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