Chapter XIV. 



Economics. Prevention and Cure. 



The economic importance of plant diseases. A few well- 

 known figures will illustrate the great economic importance of 

 the fungus diseases of plants. These include only estimates of 

 epidemics. From the nature of the case it is impossible to esti- 

 mate the smaller losses due to sporadic diseases which have 

 probably caused more total loss than the great epidemics. In 

 the kingdom of Prussia the year 1891 was particularly favorable 

 for the rust disease of cereals. In that year the loss of wheat, 

 rye, oats and barley from rust has been estimated at over one 

 hundred millions of dollars. In Australia in 1890-1891 the loss 

 by wheat rust was estimated at twelve millions. In California 

 the grape disease from 1884-1886 caused an estimated loss of 

 twenty million dollars. A single English tomato house has in 

 one season suffered a loss of a thousand dollars by fungus dis- 

 ease. An agricultural expert has estimated the yearly loss in 

 the United States due to loose smut of oats, before successful 

 treatment was discovered and introduced, at eighteen million 

 dollars. One of the most striking illustrations of the enormous 

 losses due to fungus diseases is found in the history of the 

 coffee leaf-rust disease which has played such havoc in the east- 

 ern hemisphere. It has practically exterminated the coffee 

 plantations of Ceylon where the loss from about 1870 to 1886 

 was about five million dollars yearly and the total loss in those 

 years from sixty to seventy-five million. India's annual loss 

 from wheat rust has been estimated at from two to ten million. 

 In the United States loss by wheat rust for 1891 has been placed 

 at sixty-seven millions of dollars. In our own state Dr. Lugger, 

 the late state entomologist, estimated the loss from wheat rust 

 in Minnesota in 1888 as far in excess of the total loss by ravages 

 of all insects including even the dreaded grasshopper. One can 

 realize the enormous loss from this source in an estimate by 



