THE CONTROL OF INSECT PESTS AND PLANT DISEASES. 



Few growers of crops realize the annual toll taken 

 Losses. by insects and fungous diseases. It is safe to say that 



the losses in the State of New York from these sources 

 alone exceed the amount annually appropriated by the Legislature 

 for conducting the State's business. From careful spraying experi- 

 ments conducted by the growers themselves under the direction of 

 Prof. F. C. Stewart of the State Experiment Station at Geneva, it is 

 shown that the preventable, average, annual loss to potato growers 

 in this State from blights and insects is nearly 50 bushels to the acre. 

 This represents a loss of over ten million dollars yearly, which might 

 be saved by an expenditure for spraying of less than five dollars an 

 acre. A careful estimate of losses from the loose smut of wheat in 

 this State shows that 10% of the crop is annually destroyed by this 

 fungous disease, a net loss of over a million dollars in 1909. The losses 

 from apple scab and codling moth, from San Jos6 Scale and Peach 

 Yellows, Fire Blight and all the other common insect pests and destruc- 

 tive plant diseases, if they could be accurately estimated would show 

 a grand total of appalling magnitude. This tremendous annual tax 

 upon the plant production of the State might be greatly reduced by 

 the proper application of known methods of control. 



The method of control to be employed for a given 



Methods insect pest or fungous disease must be determined 



of ControL by the nature and habits of the enemy and by the 



character of the crop attacked. Plants can seldom 

 be cured of disease as are men and animals. They must be protected 

 from the attack. If sucking insects are to be controlled something 

 must be applied that will kill when it hits them, as whale-oil soap or 

 kerosene emulsion; if biting insects are to be combated, the fruit and 

 foliage must be sprayed or dusted with a poison that when eaten will 

 destroy the pest. Many fungous diseases are prevented by spraying 

 the plants before the disease appears with a mixture poisonous to the 

 fungus but harmless to the plant. The poisons that destroy fungi are 

 seldom eflective against insects, hence we have fungicides and insecti- 

 cides. Often these can be combined in one mixture for insect and 

 fungous pests of certain crops, as, for example, arsenate of lead and 

 lime sulfur for controlling codling moth and apple scab. 



It is not to be supposed that spraying is the only means of controlling 

 diseases. Many fungi are perpetuated from year to year in or on the 



585 



