6 CIRCULAR 263, U. S. DEPARTMENT OF AGRICULTURE 
The main point appears to be that out of a given number of beds 
some at least escape severe damage, and the more beds sown at dif- 
ferent times the greater are the chances of successfully evading the 
disease. Beds located in warm areas generally make the most rapid 
recovery from mildew attack. 
TRANSPLANTING IN RELATION TO DISEASE DEVELOPMENT 
The plants are subject to mildew attack as long as they remain in 
the beds, but healthy plants usually are safe once they are set out. 
Transplanting, consequently, from mildew-free beds should proceed 
as rapidly as the plants become large enough. When beds have 
become generally infected, however, and the leaves are being rapidly 
destroyed, it is not advisable to transplant, as poor stands are likely 
to be the result. Transplanting shouldbe delayed then until the 
disease attack has subsided and the plants show definite signs of 
recovery. During 1932 heavy losses were suffered by many growers 
who attempted to transplant from beds in which the disease was still 
active, before the plants had begun to recover. * 
To hasten recovery, every effort should be made to provide good 
growing conditions. Many beds lack nitrogen toward the end of the 
season, and when this is true, an application of nitrate will help. 
The nitrate merely assists the plants more rapidly to repair the 
damage caused by the disease, and its effectiveness depends on 
weather conditions that at least temporarily check the disease. The 
nitrate should be applied after the disease attack. 
SPRAYING 
Australian authorities report that spraying for the control of 
this disease is ineffective if the disease attack is severe. Reports 
from North Carolina and South Carolina during the spring of 1932 
indicated that the control of the disease by spraying was unsatis- 
factory and in some cases caused severe injury to the plants and 
retarded plant growth. On the other hand, experiments conducted 
in Georgia and Maryland showed partial to good control of the 
disease from various sprays and dusts containing copper, and no 
injury of consequence resulted. A comprehensive program of re- 
search considering all aspects of the spray problem is in progress, 
but to reach definite conclusions will probably require at least several 
seasons of intensive effort. Meanwhile, the following program is 
suggested for those who desire to try spraying. 
Bordeaux mixture appears to be about as effective as any other 
spray or dust, and either a 3414-50 or a 46-50 formula may be 
used. The first two figures of each formula refer to pounds of cop- 
per sulphate (bluestone) and hydrated lime, respectively, and the 
50 refers to gallons of water. Applying the spray regularly every 
seven days and starting as soon as the plants are one-fourth inch 
across are suggested. These treatments may also assist in the con- 
trol of certain other leaf- -spot and plant-bed troubles. This program 
has the further advantage of insuring that the plants have some 
protection against mildew while they are small, for it is the very 
young plants that are most likely to be killed outright by the disease. 
F urthermore, young plants rarely suffer spray injury. Older plants 
