1922] GARDNER & KENDRICK—TOMATO MOSAIC 477 
previous years, well before the date when the tomato plants for 
the current season would be transplanted to the field. It is evident 
that the Physalis plants once infected constitute a perennial reser- 
voir of mosaic infection, which remains a constant danger to any 
future crops of tomatoes (or tobacco) in the vicinity. 
Further observations were made later in the season upon the 
prevalence of mosaic on the Physalis plants in fields previously 
planted to tomatoes. In the field near Lafayette in which tomato 
mosaic had occurred in 1920, 43 out of 77, or 55 per cent of the 
Physalis plants examined the third week in July showed mosaic. 
Many volunteer tomato plants had come up in this field, but among 
the 186 examined, no mosaic was found at this time, although 
later in the season a few developed the disease. 
TAGLE LE 
Physalis MOSAIC IN OLD TOMATO FIELDS 
Crop Physalis PLANTS, JULY 13, 1921 
Fretp 
1919 1920 1921 No. examined} No. mosaic ee 
eae ee Tomatoes |} Corn m 79 43 54 
AS ae igs eG Tomatoes | Oats Clover 34 7 20 
Boh ee a es Tomatoes | Corn ats 61 16 26 
Wicae ous Pea Tomatoes | Oats 27 17 63 
Wei ek Poe aes Tomatoes | Weeds 40 27 67 
CEE eo DS ea ie omatoes | Wheat 107 55 51 
a eae Not tomatoes ‘omatoes 138 34 25 
Bo es Not tomatoes Wheat 543 4 0.7 
A study of the mosaic prevalence among the Physalis plants 
was made July 13 on a large farm near Indianapolis, of which a 
considerable acreage was devoted to tomatoes in 1918, 1919, 1920, 
and 1921. The 1919 tomato crop, comprising about 100 acres, 
was practically 100 per cent mosaic in September. No observa- 
tions were made on the 1920 crop on this farm, but it is safe to 
assume that mosaic was prevalent that year. Mosaic was already 
prevalent in the 1921 crop. The results of the survey of eight 
fields on this farm and the relation between previous tomato crops 
and Physalis mosaic are presented in table I. From these data it 
is evident how prevalent mosaic may be on Physalis one and two 
