484 BOTANICAL GAZETTE [JUNE 
up showing mosaic the next year, and likewise the second year after 
the tomatoes. The disease persists among these weeds year after 
year, and such weeds serve as a perennial reservoir of mosaic infec- 
tion for future tomato crops. 
7. Mosaic has not been found to any extent occurring spontane- 
ously in Physalis, and is present in the weeds only in and near 
fields once used for tomatoes. As more and more new fields are 
used for tomatoes, however, the reservoir of mosaic infection in 
the perennial weed flora will increase each year. 
8. Evidence of spread of the disease to Physalis —— 200 to 
400 feet from tomato fields has been adduced. 
9. Ina field survey Physalis was observed in 65 out of 81 tomato 
fields, and mosaic was noted on Physalis in 35 of these fields, and 
on both Physalis and tomatoes in 29 fields. Tomato mosaic was 
noted in 60 fields, and in 48 of these Physalis was found. 
ro. In many fields the tomato mosaic was undoubtedly of 
plant-bed origin. Mosaic was found on tomatoes in plant-beds. 
Physalis is often present in and near plant-beds. 
11. Aphids and flea-beetles may play a part in the transmission 
of mosaic between Physalis and tomatoes. 
12. Physalis heterophylla was found in 7 of the 81 tomato fields 
’ examined, and in 3 fields showed mosaic. 
13. Solanum carolinense was found in 13 of the 81 tomato fields 
examined, and in one field showed mosaic. 
14. The eradication of perennial Solanaceous weeds in and near 
tomato fields, and particularly the plant-beds early in the season, 
is recommended as a mosaic control measure. 
The writers wish to acknowledge their indebtedness to Professor 
H. S. Jackson for helpful suggestions and criticism. 
PurDUE UNIVERSITY 
LaFayette, INnp. 
LITERATURE CITED 
-x. ALLARD, H. A., The mosaic disease of tobacco. U.S. Dept. Agric. Bull. 
49. Pp. 33. pls. 7- 1914. 
, Distribution of the virus of the mosaic disease in capsules, fila- 
‘iit anthers, and pistils of affected tobacco plants. Jour. Agric. 
Research §:251~256. pl. r. 1915. 
