59 



Several facts are evident from an examination of this table. After 

 the plant has acquired about eight primarj^ leaves the formation of 

 branches and of secondary leaves began, thereby multiplj^ing the 

 number of growing points. From this time on the greater part of the 

 increase in leaf area took place in the secondary leaves. By far 

 the most rapid period of leaf growth occurred at about the time when 

 squares first began to form. In Series I the average total leaf area 

 practically doubled every ten days through the seven weeks under 

 observation. In Series II the plants were older to start with, and it 

 required about forty days to double the leaf area. 



Everyone now concedes that it is useless to attempt the spraying 

 of full-grown cotton such as is represented in Series II. The extreme 

 rapidity of increase in the foliage area shown in the first part of 

 Series I shows that spraying must be repeated everj^ week or ten daj^s 

 if even one-half of the entire leaf area is to be kept poisoned. When, 

 in connection with the large per cent of daily increase, we consider 

 how much of that percentage is being unfolded at the ver}^ tip of the 

 stem; that upon that limited tip area alone will the weevil feed before 

 the formation of squares; that after the formation of squares it 

 appears to be almost impossible to poison the w^eevil's food supply; 

 and also that the irregular emergence of the weevils from hibernation 

 may extend through several weeks; it at once becomes evident that 

 poisoning' early cotton for hibernated weevils is almost as impracticable 

 as the poisoning of older cotton is now acknowledged to be. 



EFFECTS OF FEEDING UPON SQUARES AND BOLLS. 



From numerous large, open, feeding punctures a square becomes so 

 severely injured that it flares very quickly, often within 24 hours 

 (PL VII, fig. 33). Males usually make the largest punctures, which 

 they always leave open while they remain for a day or more working 

 upon the same square. It has been often found that squares thus in- 

 jured by a male will flare before the weevil leaves it. The time of 

 flaring depends upon the degree of injury relative to the size of the 

 square. Thus, small squares receiving only a single large feeding 

 puncture in the evening are found widel}^ flared in the morning. On 

 the other hand, large squares which are within a few days of the time 

 of their blooming may receive a number of punctures without show- 

 ing any noticeable flaring. Frequently a square which has flared 

 widely will be found later to have closed again and to have formed a 

 distorted bloom (PI. VII, fig. 32), and occasionally such squares de- 

 velop into normal bolls. In squares of medium size a single feeding 

 puncture does not usually destroy the square. The destruction of a 

 square by feeding results either from drying, deca}^, or a softened, 

 pulpy condition of the interior, which is the consequence of the weevil 

 injury. 



