THE CONTROL OF TOMATO LEAF-SPOT 13 
Successful spray methods for the control of tomato leaf-spot 
were worked out in 1897 and 1898 by M, B. Waite, who had identified 
this species of Septoria on the tomato on his farm in Anne Arundel 
County, Md., in 1896. His methods consisted of spraying the seed 
bed two or three times after the plants began to form rough leaves 
and spraying the crop about three times after the plants had begun 
to form foliage rapidly. This was on late tomatoes, which not in- 
frequently become heavily infected in the seed bed. 5 
The heavy leaf-spot epidemics occurring on tomatoes grown for 
the canneries nowadays are difficult to control with fewer than five 
field applications of spray mixture, especially when they are started 
fairly early; and under these circumstances the later applications 
are more effective than those applied in the early part of the 
season. Moreover, 100 gallons of 1 1 50 Bordeaux mixture per acre 
at each application are more effective than 50 gallons, the quantity 
Fig. 7. — Two adjoining fields of tomatoes on the same farm : A, Unsprayed ; plants 
defoliated by leaf -spot : B, sprayed ; plants healthy 
usually applied. The effectiveness of Bordeaux mixture is still fur- 
ther improved by adding to each 50 gallons of spray liquid 2 or 3 
pounds of rosin-fishoil soap, which facilitates spreading. The soap 
should be dissolved in a small quantity of hot water before it is added 
to the mixture. 
The increased yields obtained by spraying tomatoes from 1916 to 
1918 in the Middle Atlantic and Middle Western States by the 
United States Department of Agriculture (#), State experiment sta- 
tions, and certain large manufacturers of tomato products, working 
cooperatively, are summarized in Table 4. They represent about the 
average increases that may be expected from spraying tomatoes in 
this region. 
In these experiments spraying increased the yield from 6.9 to 47 
per cent. The increase of 6.9 per cent was obtained in a field in 
which leaf-spot did not appear until near the end of the picking 
season. Consequently there was little injury and little gain. Al- 
though the results were variable, the average increase in the other 
fields was about 30 per cent. From these experiments it would seem 
that thorough spraying in this region would usually increase the 
yield from 20 to 25 per cent. 
5 Oral statement to the writers. 
