CATALOGUE OF INSECTS 15 



CHAPTER III. 



INJURY CAUSED BY INSECTS. 



The fact that farm crops are annually shortened to a considerable 

 extent by insect attack is common knowledge ; the percentage of 

 injury has been variously estimated from 10 % to 50 %, and both are 

 accurate and yet incorrect, for injury varies in the same locality and 

 on the same crop from year to year. As an example, the pea crop in 

 1899 was in many sections of our State cut from 10 % to 30 % by a 

 plant louse which had never before done any appreciable injury and 

 had not been even described ; it is not probable that without a dupli- 

 cation of the weather conditions existing in the spring of that year, a 

 similar percentage of injury will occur for a long time to come. In 

 some seasons the melon plant louse destroys the crop completely over 

 large areas, while in others there is little injury noticeable. Thus 

 the percentage varies with the years and with the species ; but there 

 are no years when some crop does not suffer heavily, and some 

 species, like the codling moth and plum Curculio, exact toll annually ; 

 so we will be easily within bounds if we estimate the annual short- 

 ening of farm crops in our State as ranging from 20 % to 25 %. It is 

 also important to note that this injury is more severe than the figures 

 would indicate, since the shortage is largely the profit. The cost of 

 planting, fertilizing, cultivating, and often of harvesting, is the 

 same ; what is gone is the 20 % or 25 % that would have been almost 

 clear profit had it been there. 



Insect injury may be either to quantity or to quality of the crop, 

 and the importance of the latter is not sufficiently understood. A 

 basket of wormy apples costs to put into market exactly as much as 

 a basket of first-class fruit ; yet the difference in price in a full 

 market often equals 50 % and sometimes even more. Corn that is 

 gnawed by caterpillars or cantaloupes undersized and sooty from plant- 

 lice attack are left unsold until nothing better is attainable, or is pur- 

 chased only because the price is much below what better products are 

 bringing. Sightliness goes a long way with the average buyer, and 

 quality is often secondary if a product is perfect in form. I have 

 emphasized this point, because it is one in which the greatest im- 

 provement can be effected and in which the percentage of loss can be 

 much decreased. 



Insect injury to quantity is much the most obvious and is the one 

 most usually complained of by the farmer. A striking example of 



