THE RED SPIDER ON COTTOK. 



11 



1 inches high. In both 1011 and IDlii the pest abandoned cotton 

 about the Last of August. This makes the period of activity cover 

 about 12 weeks. 



NATURE OF DA^FAGE. 



The presence of the pest on cotton is first revealed b}' the appear- 

 ance on the upper surface of the k\af of a blood-red spot. As leaves 

 become badly infested thev redden over the entire surface, become 



Fig. 6. — a. Cross section of norniiil cotton loaf ; b, cross section of cotton loaf injured by 

 the red spider. The puncture is near lower right-hand comer. Ilishly magnified. 

 (Author's illustration.) 



distorted, and drop. Figure 5 shows an uninfested cotton plant for 

 comparison with figure 7, infested. The lower leaves usually are first 

 attacked, but infestation spreads upward until often only the bare 

 stalk and one or two terminal leaves remain. (See fig. 8.) Such 

 plants almost invariablv die. The injury to the leaf and the dis- 

 coloration which follows the feeding of the mites are easily under- 

 stood by referring to figure 6, which represents ,(«) the appearance 

 of healthy cotton leaf-tissues and (h) the condition of the tissue 

 after feeding by the pest. As previously intimated, the worst spots 

 of infestation are either to be found in close jiroximity to yards Avith 

 borders of violets or to a clump of pokeweed stalks. Large fields are 

 prol)ably never completely damaged, but smaller fields frec^uently 

 become wholly affected. A thorough examination of all Hehls within 

 1 mile of the center of Leesville. S. C\. was made with a view of deter- 

 mining the exact status of red-spider infestation at one sjiecific 



