6 THE RED SPIDER ON COTTON. 



HIBERNATION VERSUS WINTERING. 



Some observers have thought that the red spider commonly hiber- 

 nates in trash or in the soil in cotton fields, but the past season's 

 investigations have produced absolutely no evidence to support this 

 idea. During the early spring, before the active season for the red 

 spider commenced, trash was several times taken from fields in which 

 the infestation had previously been severe and examined with great 

 care. A few minute dormant acarids and other forms were thus 

 obtained, but no red spiders could be found in such material. Simi- 

 larly, during December, 1911, ample quantities of trash, etc., from 

 recently infested fields were carefulh^ examined, but always without 

 finding any trace of the red spider. That this pest remains more or 

 less actiVe throughout the winter there can be no doubt. Mr. G. A. 

 Runner found active adults at Batesburg, S. C. on December 21, 

 1909. Mr. H. F. "Wilson observed red spiders feeding in early Feb- 

 ruary at the same locality. The writer found all stages on violets on 

 March 11, and adults as late as December 19, on the same host at 

 Batesburg. The finding of the active red spiders during the coldest 

 weather is certainly an additional indication that hibernation does 

 not take place in South Carolina. 



DISPERSION. 



How do red spiders become established upon cotton? They have 

 no wings and their legs are very minute. Close observations reveal 

 that on the ground they normally travel at the rate of 1 inch per 

 15 seconds, which, if maintained, would total 480 feet in 24 hours. 

 Red spiders are doubtless occasionally transferred by dogs, chickens, 

 other domestic animals, insects, and birds. Strong winds may serve 

 occasionally to transfer them from plant to plant. It is the writer's 

 firm belief, however, that the chief means of dispersion is the red 

 spider's own efforts. When once established in a field they may be 

 further distributed by farm hands and by stock while cultivation is 

 being carried on. They also spread from plant to plant along the 

 interlacing branches, but traps specially prepared with " tangle- foot " 

 and placed in the field have proven that individuals commonly crawl 

 from plant to plant by way of the stalk and the groimd. 



Since the red spider apparently uses no instinct or intelligence in 

 finding cotton plants, it follows that the pest must hit upon the cotton 

 stalks entirely by chance. The result of this haphazard manner of 

 migration must necessarily'- result often in the penetration of the 

 spiders far into the center of fields, thus giving rise to the mistaken 

 impression that they had hibernated at these points. 



Furthermore, as the likelihood of the discovery of cotton by the 

 spider is doubtless in proportion to the thickness of the '' stand," it 



