48 
Journal of Agricultural Research 
Vol. XIV, No. I 
tic symptoms of blight. These results indicate that M. solanifolii on the 
wild mustard plants were still virus bearers, although they or their 
parents had not fed on spinach for some time, as the spinach in this field 
had been cut early in March. Inoculations with juice of the mustard 
plants gave negative results. 
INFECTIOUS ENTITY OF SPINACH-BRIGHT MAY BE CARRIED FROM SPRING 
TO FAU, BY A DIRECT DINE OF APHIDS 
On April 6, 1917, a blighted plant was obtained from farm B and 
brought to the greenhouse to use for inoculations. One adult of Macro- 
siphum solanifolii was removed from the blighted plant and placed on 
the larger of two spinach plants 74 days old, growing in a pot. A similar 
pot of plants served as a control. Both of the plants in the pot to which 
the aphid was transferred developed positive symptoms of blight, while 
the controls remained healthy. 
On May 7, 1917, both of the inoculated plants were in advanced stages 
of blight. The direct descendants of the adult aphid, used for the 
inoculation on April 6, were abundant on these blighted plants. On 
May 7 some of these direct descendants were transferred from the blighted 
spinach plants to a small potted eggplant which had been grown in a 
large cage under insect-free conditions. This eggplant was then removed 
from the pot and transplanted to the soil in a field cage which was free 
from spinach. Several potato tubers were planted in the soil about the 
eggplant. On May 14 several Ruby King pepper plants which had been 
grown under insect-free conditions were transplanted to the above field 
cage, and to them were transferred young aphids from the eggplant. 
These aphids were kept in a field cage and allowed to reproduce and feed 
only on eggplant, pepper, and potato plants during the summer. 
On August 9, 1917, a number of the above aphids in various stages of 
development were transferred to healthy spinach seedlings growing 
under insect-free conditions in another field cage. Similar seedlings in 
another field cage served as controls. On September 1 some of the 
plants to which the aphids had been transferred on August 9 were 
slightly mottled, while the control plants were of a normal green color. 
Hie aphids multiplied rapidly on the spinach plants in the field cage, 
and by October 1 the majority of the plants had died without showing 
any decided mottling. On October 6 new spinach seed grown in New 
York State was broadcasted in this cage and raked into the soil. A thick 
stand of spinach seedlings came up in six days. To these seedlings the 
aphids migrated from the few yellowish plants which still remained 
alive. On November 10 a few of the plants from the broadcasted seed 
had developed the mottled leaves characteristic of blight. On November 
15 a considerable number of the seedling plants in this cage had yellow 
cotyledons, and the true leaves of many were distinctly mottle^. At 
this time only one of the original plants growing in this cage remained 
