1922] GARDNER & KENDRICK—TOMATO MOSAIC 483 
pulling. This is especially important during the first part of the 
season, since early mosaic infection results in the greatest loss. 
These perennial species present extreme difficulties in the way 
of control because of the deep rootstocks and the prompt reappear- 
ance of new shoots after the old ones are destroyed. 
The annual Solanaceous weeds, such as nightshade and certain 
ground cherries, should be destroyed in and near tomato fields and 
plant-beds. 
Hothouses to be used for tomatoes should be kept free from 
Solanaceous weeds. 
Tomato plant-beds should be cleared of all weeds and remain- 
ing tomato plants as soon as no more transplants are needed. 
Transplants from plant-beds in which mosaic is present should 
not be used. 
Theoretically these weed relationships are’ equally important 
in connection with the control of mosaic in tobacco. 
: Summary 
1. Tomato mosaic may be carried over winter in hothouse 
tomato crops, but this does not account for the great bulk of mosaic 
infection in the canning crop. 
2. In a total of 22,944 tomato plants grown from seed from 
mosaic plants, no evidence of seed transmission of the disease was 
obtained 
3. The mosaic disease has been found occurring in the field on 
the following perennial weed relatives of the tomato in Indiana: 
Physalis subglabrata, P. virginiana, P. heterophylla, and Solanum 
carolinense. Mosaic has been transmitted to tomatoes from each 
of these species. 
4. It has been proved that the mosaic virus persists over winter 
in the rootstocks of P. subglabrata. The young mosaic shoots 
appear in the spring before tomatoes are transplanted to the field. 
From these shoots the disease has been transmitted to tomatoes. 
5. Physalis subglabrata, with some admixture of the very similar 
P. virginiana, is a very prevalent weed in Indiana tomato fields. 
6. Examination of these weeds in fields previously in tomatoes 
shows that a considerable percentage of the Physalis plants come 
