6 PAPERS ON THE COTTON BOLL WEEVIL^ ETC. 



If during September and early October there should be a normal or 

 excessive rainfall and the plants keep growing, there will be plenty of 

 squares upon which the weevils may breed and multiply until frost 

 occurs. If, on the other hand, during this period the weather should 

 be hot and dry, the plants will stop growing and those infested squares 

 which fall to the ground will be quickly dried up and but a relatively 

 small number of weevils Avill be produced. This was strikingl}^ shown 

 in observations upon the number of weevils on cotton at the college in 

 the fall of 1903 as compared with the fall of 1904. During Septem- 

 ber, 1904, there was an average of not over 3 squares to a plant, 

 whereas in September, 1903, there was an average of about 40 squares 

 to a plant. At this time during these two seasons there was approxi- 

 mately the same number of weevils in the field; but it can be readily 

 seen that with so few squares in which to breed, in September, 1904, 

 there would be far fewer weevils developed after September to go into 

 hibernation. 



Mr. Louis Teltschick states that in Lavaca Count}^ Tex., at the time 

 he turned cattle in to graze his cotton, October 17, 1903, there were 

 about 2 weevils to a stalk. Concerning this he writes as follows: 



I will state in this connection that in my opinion the bulk of the w^eevils had then 

 left the cotton. I think that during the last three years the majority of weevils 

 began leaving the cotton as early as September 1. They were undoubtedly com- 

 pelled to do this by a scarcity of squares. To be more explicit I give you the follow- 

 ing figures: On August 28, 1904, I estimated the number of weevils in my field at 12 

 per stalk. While I made no such estimate in 1902 or 1903, considering the extent of 

 the injury worked by them in those years, I think that their numbers on the same 

 date might safely be put at 6 for 1902 and 9 for 1903. When I cut the stalks early in 

 October, 1902, I found that there were about I2 weevils per stalk, and in October, 

 1903, when I turned the cattle in, there were about 2 weevils per stalk. You will see 

 that according to these estimates from 75 to 80 per cent of the weevils infesting the 

 fields on August 28 in those years had disappeared by October 15, leaving out of 

 account all weevils hatched between the two dates. Where they went or what be- 

 came of them I am unable to say. They may have gone to uninfested regions, or 

 they may have died or gone into hibernation quarters when squares became too 

 scarce to supply all of them. 



These observations merely confirm our previous statement that the 

 number of weevils in the fall is controlled entirely })y the food suppl3^ 



One of the principal factors in cutting off the food suppl}^ of the 

 boll weevil in the fall is the cotton leaf-worm or so-called "army 

 worm" (Alahama argillacea Hbn.). \¥hereas this insect was formerly 

 considered to be the great scourge of the cotton planter, it may now 

 be said to be an almost positive advantage in territory affected b}^ the 

 boll weevil, as its injury does not ordinarily occur until after the crop 

 has been made, and all further fruiting would be prevented by the boll 

 weevil. As soon as the leaf worms have stript the cotton of foliage 

 and squares the weevils either die or leave for fields where the}^ may 

 obtain food. This was strikingly shown in an examination of four 



