23 



per cent of the corn crop throughout the United States, not taking 

 into account the injury from rain, molding, etc., following this attack. 

 The value of the corn crop of the United States in 1899, as reported 

 by the Twelfth Census, was $828,258,326. Two per cent of this 

 amount is 116,565,166, which may be held to represent approxi- 

 mately the loss annually occasioned by this insect to the corn crop of 

 the United States. 



INJURY TO COTTON. 



Notwithstanding its large aggregate injury to corn, the boll worm is 

 best known as an enemy to cotton. Injury to this crop is largely 

 b}^ the third and fourth generations of larvae. With the general 

 hardening of field corn in late July the moths go to the cotton fields, 

 where they feed on the nectar secreted by the squares and flowers, and 

 eggs are deposited almost indiscriminately over the plants. Notable 

 injur}^ to cotton usually begins early in August, and may at this time 

 be very severe, gradually becoming less toward the end of the month 

 as the larvae mature and pupate, or die of parasitism or from other 

 causes. The injur}^, however, may at no time be very pronounced, 

 but continue during August and well into September. This condition 

 appears to result from the relative age of the surrounding corn. If 

 all of the neighboring fields mature at about the same time, injury to 

 cotton in that vicinity will likel}^ be much more evident than if these 

 mature irregularly. It should here be noted that the occurrence of 

 rains and showers during late July and early August appears greatly 

 to favor boUworm injury to cotton. This point will be dealt with 

 more fully on page 32. 



At the present time the bollworm is more especially destructive to 

 cotton in the following States, given in about the order of importance 

 of injur}^: Texas, Louisiana, Indian Territory, Oklahoma, Mississippi, 

 and Arkansas. In the States of Alabama, Georgia, Florida, and the 

 Carolinas bollworm injury to cotton is probably not ordinarily very 

 extensive. With the exception of a portion of Alabama, the general 

 planting of late corn for fodder and silage furnishes the insect with 

 a succession of its favorite food, with the result that cotton is not 

 seriously attacked, except locally under certain readily explained 

 conditions. 



In the first-mentioned States, however, the simple planting of early 

 corn and cotton, largely to the exclusion of other crops, furnishes just 

 those conditions most favorable for the development in large numbers 

 of the bollworm, and its severe injuries are due in no small degree to 

 the kind of farm practices there in vogue. 



During the years 1903 and 1901, the period covered by this investi- 

 gation, boll worm injury in certain sections of Texas varied from 8 to 

 60 per cent of the crop. The injury, on the whole, was much more 



