92 



THE EFFECT OF WEEVIL WORK ON COTTON. 



The recognition of the presence of the boll weevil may de- 

 pend upon the identification of the adults or the immature 

 stages in squares and bolls or just as certainly upon the 

 recognition of its feeding injuries or the eflFect of its work 

 upon the fruiting of the cotton, as these are also charac- 

 teristic. No other insect produces at all similar injuries to 

 cotton. 



The excrement deposited by the adult weevils on the 

 squares upon which they work is of a bright orange color 

 and so forms a conspicuous sign of boll weevil presence. 

 The egg punctures, like those made for feeding, are eaten out 

 but are only made large enough to receive the egg which is 

 placed just inside of the floral coverings and usually near 

 the base of the bud. The natural tendency of the green 

 parts of plants to heal wounds in which decay does not oc- 

 cur causes a gi'owth of plant cells to more than fiU the ca- 

 nal leading to the egg cavity. The excess of this growtb 

 bulges outward so that it forms a distinct ''wart". This 

 '•wart" is therefore characteristic of a boll weevil egg punc 

 ture. As the grub feeds and gTOws inside the bud it de- 

 stroys the very heart of the square, until when about half 

 grown its injury thereto becomes so great as to cause the 

 destruction of that bud. The leaflets enclosing the bud 

 spread apart, or "flare" as it is called, and the whole square 

 turns yellow, wilts and is shed as are lea\'es when they can 

 be of no further use to the plant. It is Nature's surgery 

 in removing a diseased and useless member. TTpon the 

 ground the development of the grub continues and its trans- 

 formation through the pupal stage to the adult beetle takes 

 place. Practically one-half of the developmental period is 

 spent in the square on the plant and the other half in the 

 •square after it has fallen to the ground. Badly infested 

 cotton produces few, if any, blooms, while the infested 

 squares shed by the plant as fast as they form are thickly 

 scattered beneath it on the ground. Squares may be shed 

 as a result of adverse cultural or climatic influences, but 



