212 



Minnesota Plant Diseases. 



without injury to the host plant. Only the best-known and 

 well-established formulae will be considered here. For de- 

 tailed accounts of the action on specific diseases, the special 

 portion of this work should be consulted, as also the experi- 

 ment station bulletins of the Department of Agriculture. A 

 great many of the bulletins of the Department of Agriculture 

 and of the various Experiment Stations have been consulted in 

 compiling these formulae. These may be referred to for fur- 

 ther detail. 



The value of spraying in agricultural and horticultural work 

 has been proven to be considerable. It is no longer a chance 

 but a certainty. The kind of spray and number of applications 



FIG. 103. A knapsack pump. (The Goulds Mnfg. Co.) 



must be left to the judgment of the operator. In general, bor- 

 deaux is of greatest use. Knowledge and intelligent judgment 

 on the part of the agriculturalist are indispensable. He must 

 be prompt in his action and, if possible, must extend his knowl- 

 edge so as to forestall any disease and thus save time, labor 

 and expense. It is usually best to spray too often than too 

 seldom. Timely application may kill thousands of spores and 

 prevent infection when a late application may be of no avail. 

 Prevention is always to be desired. Applications must be thor- 

 ough. Such a treatment usually requires but a little more at- 



