482 BOTANICAL GAZETTE [JUNE 
fields. In three fields, all in Marion County, mosaic was noted on 
P. heterophylla and also occurred on the tomatoes. In one of these 
(field no. 7) ten P. heterophylla plants were noted and one showed 
mosaic. Mosaic was noted on S. carolinense in only one field, a 
garden near Kokomo in which mosaic also occurred on P. sub- 
glabrata and on the tomatoes. It is evident that P. heterophylla 
and S. carolinense may function as reservoirs of mosaic infection. 
Both species are perennial by deep rootstocks and difficult to 
eradicate or control by cultivation. 
Mosaic in annual Solanaceous weeds 
ALLARD (1) transmitted mosaic from tobacco to two garden 
species of Physalis (probably annuals) and to the annual Solanum 
nigrum and Datura stramenium. In Indiana mosaic has frequently 
been noted on these weeds. Attempts to cross inoculate from 
D. stramonium to tomato and vice versa have yielded negative 
results. In preliminary tests mosaic has been transmitted success- 
fully from tomato to S. nigrum and to S. integrifolium and Lyco- 
persicum pimpinnellifolium. Mosaic has been noted on cul- 
tivated Physalis pubescens. The disease, of course, is common 
on tobacco, and has been transmitted to tomatoes by artificial 
inoculation. Mosaic has been noted on tobacco plants occurring 
as weeds in hothouses. While annual hosts cannot carry the mosaic 
disease over winter, they may serve as sources of infection during 
the growing season, and aid in the annual spread of the disease. 
Annual Solanaceous weeds are undesirable in tomato fields and 
plant-beds and in hothouses. 
Mosaic control suggestions 
The danger involved in growing plants for the field tomato 
crop in hothouses used for tomatoes should clearly be understood. 
Tomato growers should recognize in the perennial ground cherries 
and horse nettle a distinct danger to their crop. Drastic measures 
should be taken to eradicate these weeds in the vicinity of tomato 
seed-beds and plant-beds. Furthermore, during the early part of 
the season these weeds should be destroyed or at least kept down in 
and around the tomato field by frequent cultivation and hand 
