RED SPIDER ON COTTON AND HOW TO CONTROL IT, 



Fig. 4.— Cotton plant in an early stage of infesta- 

 tion by the red spider. Many leaves are discol- 

 ored and some of the lower ones have dropped. 



SEASONAL HISTORY AND HABITS. 



The red spiders which pass 

 through the winter are chiefly 

 the mature females. Males, 

 however, may also be seen at 

 times during this season, and, 

 indeed, during periods of mild 

 weather eggs are laid and con- 

 siderable development, may take 

 place. Upon several occasions 

 at Batesburg, S. C, all stages 

 of the red spider have been seen 

 in winter on plants in outdoor 

 locations. Feeding contmues 

 more or less, depending on the 

 temperature, on several species 

 of plants which bear leaves 

 throughout the winter. 



The great majority of red spi- 

 ders pass the winter on wild 



plants, and since these plants support th(^ mite durmg the time of year 

 when it is most difficult for the pest to survive, it is clear that 

 they are of great importance. Among the more common of these 

 winter plants are hedge nettle, evening primrose, Jerusalem oak, wild 

 blackberry, sow thistle, wild geranium, and wild vetch. 



With the return of warm spring days the red spiders multiply much 

 faster, until their winter food plants become too crowded to support 

 them properly. New feeding grounds then become necessary, and 



migrations take place, which carry them 

 to numerous species of spring plants 

 and weeds. 



The first spring generation of females 

 usually develops about March 31. 

 From this date until about May 31, 

 when cotton becomes attractive to the 

 pest, the red spider advances from the 

 winter plants in several successive mi- 

 grations. Durmg this interval five 

 broods of red spiders usuaUy develop, so 

 that each wintering female by the fh'st 

 of June has produced, theoretically, 

 more than 300,000,000 offspring. In 

 Fig. 5.-cotton plant in well advanced the meantime most wceds and garden 

 stage of infestation by the red spider, plants that stand in the path of the red 



Nearly all leaves, squares, and liolls have . , , ^ -, i •i-.i 



been shed. spider s advance have become miested. 



