July 1,1925 Overwintering and Dissemination of Cucurbit Mosaic 
57 
Wisconsin but occur in southern Michigan and northern Indiana. 
The pokeweed is common in southern Indiana and in the cucumber¬ 
growing sections of southern Illinois, 'where it seems to be an important 
source of infection to the cucurbits. 
Cucurbit mosaic also lives over winter in the roots of catnip (Nepeta 
cataria) and certain perennial species of Physalis. 
In cross-inoculation experiments with plants of the Cucurbitaceae, 
all species tested have proved to be susceptible to mosaic except 
those of the genus Citrullus. Infection has been produced in 11 
genera, including 23 species and 96 horticultural varieties. 
Successful cross inoculations have been made from mosaic cucum¬ 
bers to the Martynia louisiana, pigweed (. Amaranthus retrojlexus ), 
and pepper ( Capsicum annuum). 
The pepper is also susceptible to tobacco mosaic, and it has been 
found that pepper plants may be infected with tobacco mosaic and 
the disease then transmitted from them to either tobacco or cucum¬ 
ber. Similar results were obtained from pepper plants inoculated 
with cucurbit mosaic, and the results indicate that the infective 
principle of tobacco and cucurbit mosaic are intertransmissible. 
There is no evidence of seed transmission of mosaic in the case of 
martynia, pepper, or pigweed, and as these plants are annuals they 
do not seem to be concerned in overwintering mosaic. These annual 
hosts, when infected with mosaic, however, often act as sources of 
infection to cucurbits during the summer. 
Experiments on the control of cucurbit mosaic by removal of the 
wild hosts on which it overwinters are now in progress. 
LITERATURE CITED 
(1) Allard, H. A. 
1914. the mosaic disease of tobacco. U. S. Dept. Agr. Bui. 40, 33 p., 
illus. 
(2) - 
1918. the mosaic disease of Phytolacca decandra. Phytopathology 
8: 51-54, illus. 
(3) Butler, E J. 
1923. some characteristics of the virus diseases of plants. Sci. 
Prog. 17: 416-431. 
(4) Clinton, G. P. 
1915. CHLOROSIS OF PLANTS WITH SPECIAL REFERENCE TO CALICO OF 
tobacco. Conn. Agr. Exp. Sta. Ann. Rpt. 1914: 357-424, illus. 
(5) Doolittle, S. P. 
1916. a new infectious mosaic disease of cucumber. Phytopathology 
6: 145-147. 
(6) -and Gilbert, W. W. 
1918. further notes on cucumber mosaic disease. (Abstract) 
Phytopathology 8: 77-78. 
(7) -and Gilbert, W. W. 
1919. SEED TRANSMISSION OF CUCURBIT MOSAIC BY THE WILD CUCUMBER. 
Phytopathology 9: 326-327. 
( 8 ) - 
1920. the mosaic disease of cucurbits. U. S. Dept. Agr. Bui. 879, 69 
p., illus. 
(9) - 
1921. THE RELATION OF WILD HOST PLANTS TO THE OVERWINTERING OF 
cucurbit mosaic. (Abstract) Phytopathology 11: 47. 
(10) -and Walker, M. N. 
1922. notes on cucurbit mosaic. (Abstract) Phytopathology 12: 
42-43. 
(11) -and Walker, M. N. 
1923. cross-inoculation studies with cucurbit mosaic. Science 57: 
477. 
