Department of Agriculture 41 



The Red Spider (Tetranijchus telanus) 



In some localities, a small mite called the red spider attacks 

 cotton, causing a yellowing of the leaves by sucking the juices 

 of the plant. Considerable webbing will be found on the 

 under sides of the leaves on heavily infested plants. 



If this pest threatens to do serious damage, it can be con- 

 trolled by the application of lime sulphur dust, or even plain 

 flowers of sulphur. 



The Cotton Stainer (Dysdercus suturellus) 



Prior to the arrival of the boll weevil, the cotton stainer 

 was one of the principal pests of Sea Island cotton in Florida. 

 Lint from bolls sucked by this insect is stained and of infe- 

 rior grade. At one time it was thought that the stain was 

 caused by a secretion of some sort, produced by the insect, 

 but it is now thought to be caused indirectly by leakage 

 from the immature seed that have been pierced by the suck- 

 ing tube of the stainer. Both adults and nymphs will cause 

 the stain. If care is not exercised in picking stainer-infested 

 cotton, the insects will be picked with the cotton, and subse- 

 quently crushed by the gins, which will further damage the 

 lint. 



Description and Life History 



The adult stainer is a dull red insect about % of an inch 

 long, and a little less than half as broad. Markings on the 

 wings form a characteristic X on the adult insect's back 

 when they are folded. Prominent white crosswise stripes 

 give both the adults and nymphs a rather distinctive appear- 

 ance. 



The stainer passes the winter in both the adult and nym- 

 phal stages. It feeds on a wide variety of plants, but appar- 

 ently multiplies much more prolificily on some foods than 

 others. In discussing the stainer, one text book on entomol- 

 ogy states : "Since cotton seed has become almost as valuable 

 as cotton itself, and is now completely used up, it has been 

 found that these insects have become practically harmless. 

 It seems that they were enabled to multiply unduly in heaps 

 of decaying cotton seed, and since at present no such heaps 

 exist they cannot increase so rapidly." 



Adult stainers move into cotton more or less gradually 

 from surrounding host plants which die or otherwise become 

 unsuitable as food. They feed on all parts of the cotton 

 plant, but appear neither to multiply rapidly or do much dam- 



