THE RED SPIDER ON COTTON. 59 
reaching the tip of the branch or leaf they fairly overrun one another 
and become ensnared in the web spun by the later arrivals. In the 
case of the perennial pea (Lathyrus latifolius), the swarming con- 
tinued until fully half of the area of the terminal leaflets was envel- 
oped. A typical terminal leaflet was carefully examined and meas- 
ured. The swarm was found to be built out to a thickness of 0.25 
inch beyond the surface of the leaf, and all mites within the mass were 
dead. One such swarm was found to contain about 15,000 mites. 
Innumerable thousands of red spiders are eliminated in this manner. 
Fic. 21.—Ideal outfit for spraying cotton fields: Barrel pump with double lead of hose mounted on 
dismantled hayrake. (Original.) 
REMEDIAL MEASURES. 
PREVENTIVE. 
Titus, in 1905, was the first investigator to advocate the applica- 
tion of cultural methods as a means of controlling the red spider. He 
suggested the rotation of crops, elimination of all plant, weed, and 
grass erowth near fields during the winter and early spring, and fall 
or winter plowing to turn under all vegetation. Worsham (1910) 
also strongly recommended the destruction of all winter food plants 
in proximity to infested cotton fields. | 
We have already shown that red spiders readily establish them- 
selves on several of the native and dooryard plants. These hosts 
serve as sources of dispersion. By destroying, during the winter and 
early spring, pokeweed, Jerusalem oak, Jamestown weed, wild black- 
berry, wild geranium, and other plants which breed the pest, much 
good will be done. This plan has been tested by the writer in sev- 
eral instances and has given complete immunity the following season. 
Ewing (1914) states that this idea was tried in hop fields in Oregon, 
with the result that the part of the field that was well cleared of for- 
