23 



STEM BORER. 



Insects boring into the stem of the cotton plant have not 

 been observed until recently, although a careful watch has 

 been kept for this class of injury. After a recent wind storm 

 many broken stems and branches in the station planting 

 revealed the work of a small black beetle, Sinoxylon conigerum 

 Gerstacker. This beetle attacks dead wood and felled and 

 seasoning timber, having been taken on previous occasions from 

 Acacia decurrens, Prosopis juliflora and cotton stumps. It was 

 probably attracted to the standing cotton because of the dry 

 condition of the wood through lack of irrigation. The attacks 

 are almost without exception at the origin of a branching shoot, 

 and as the attacks of two or three beetles are usually concen- 

 trated at one point they may do great havoc in a plantation 

 before their work is observed. At the same time it is not 

 believed that they will attack actively growing plants and if 

 this is so their injuries may be entirely avoided by keeping 

 the land in good tilth so as to conserve its moisture. 



Thrips. A species of Thrips is commonly found in the blos- 

 soms of cotton but seems to do very little damage. Specimens 

 of the insect were referred to Washington for determination. 



MINOR PESTS. 



Red spider. A species of 

 Tetranychus is also commonly 

 found on the foliage or bolls of 

 cotton. It is probably respon- 

 sible for some spotting of these 

 parts of the plant but outside 

 of this does little damage, and 

 has never been observed in 

 large numbers. Specimens of 

 this pest were also referred to 

 Washington for determination. 



Fig. 15 — Mite or red spider, Tetranychus 

 sp., found on cotton in Hawaii. (Photo- 

 graph by author). 



Besides the injurious spe- 

 cies already referred to there 

 are three or four insects com- 

 monly found on or about cot- 



