146 DISEASE IN PLANTS. 



It would be tedious to attempt anything like 

 a complete account of the estimates of loss in 

 different countries, due to the ravages of insects 

 and fungi, but the following examples should 

 surely serve to convince anyone of the magnitude 

 of these losses and of the economic importance 

 of the whole question, and the reader may be 

 referred to the special literature for further 

 details. 



The coffee leaf-disease of Ceylon, due to the 

 fungus Hernileia^ is estimated to have cost that 

 Colony considerably over ;^i, 000,000 per annum 

 for several years. One estimate puts the loss in 

 ten years at from ;^i2,ooo,ooo to p^i 5,000,000. 

 The hop-aphis is estimated to have cost Kent 

 -^2,700,000 in the year 1882. In 1874 the 

 Agricultural Commissioner of the United States 

 estimated the annual loss, due to the ravages of 

 insects on cotton alone, to amount to -^5,000,000; 

 and in 1882 the annual loss to the United 

 States due to insects, calculated for all kinds of 

 agricultural produce, was put at the appalling 

 figure of from ^^40,000,000 to ^60,000,000 

 sterling. In India, the annual loss due to 

 wheat-rust alone has recently been estimated at 

 4,000,000 to 20,000,000 rupees, and one insect 

 alone is said to have cost the cotton planters a 

 quarter of the crop valued at seven crores of 

 rupees in bad years. Similarly, in Australia 

 the annual loss from wheat-rust has been put 

 at from ;^2,ooo,ooo to ;^3,ooo,ooo. In 1891 

 the loss in Prussia alone from grain-rusts was 



