THE FIELD TESTING OF COPPER-SPRAY COATINGS. 7 



CELERY AT BRADENTOWN, FLA. 



Figure 4 shows the behavior of Bordeaux mixture on celery at 

 Bradentown, Fla., in February and March, 1918. Each grower 

 prepared and appHed the mixture in his own way to plantings of 



Fig. 4.— Field tests for copper on celery leaves. Four fields were sprayed by the owners with Bordeaux 

 mixture supposedly made up in each case with 6 pounds of bluestone in 50 gallons. A hypothetical 

 safety zone is indicated between the 35 and 45 milligram tests. The actual determinations are indi- 

 cated by O, the estimated interpolations by X. 



1 or more acres. In every case the grower claimed that 6 pounds 

 of bluestone were used in 50 gallons of the Bordeaux mixture. Knap- 

 sack sprayers were used. With the exception of field D one or 



