THE RED SPIDER ON COTTON. 67 



pump carried through the field on a wagon or on a specially con- 

 structed vehicle of some sort. Figure 21 , page 59, is from a photograph 

 of a portable outfit devised by a progressive planter at Laurinburg, 

 N. C, from suggestions suppUed by the writers. It consists of a plat- 

 foiin built upon the axle and shafts of a dismantled hayrake. The 

 two wheels are large, bringing the axle well above the ground, so that 

 injury of the plants is avoided to a great extent. A barrel pump 

 with a capacity of 50 gallons is momited on the platform. A boy 

 drives, one man pumps, and one handles each sprayer, of which pref- 

 erably there should be two. Thorough treatment of 3 or 4 acres a 

 day was readily obtained with this device. For safe work the attempt 

 should not be made to use this device in cotton of tall growth, since 

 the passing wagon will injure high plants, but it is ideal in fields of 

 average height or less. 



Some dissatisfaction has been experienced among certain of those 

 who have undertaken to check the ravages of the red spider by 

 spraying. This can be understood on account of the extreme care 

 which must be exercised in order to secure effective results. From 

 the fact that the mite as a rule passes its entire existence upon the 

 underside of a single leaf, it becomes plainly necessary in spraying to 

 Tiit the entire underside of every leaf of an infested plant. Furthermore, 

 since we have shown that no safe insecticide is known which will 

 destroy red spider eggs, it is clear that a second spraying is necessary 

 to kill the individuals which were eggs at the time of the first spraying. 



SUMMARY AND RECOMMENDATIONS. 



The common red spider occurs throughout the United States, but 

 is known as a serious pest in only three regions, namely: In that 

 portion of the cotton belt including North Carolina, South Carolina, 

 Georgia, Florida, Alabama, and Mississippi, where it is primarily a 

 pest of cotton; in north-central and western Colorado as a pest of 

 fruit trees; and in central California, where the species is a rather 

 serious pest of hop fields. 



It is estimated that during a season of severe red-spider occurrence 

 the loss to the cotton planters of the Southeast amounts approxi- 

 mately to S2,000,000. 



From the records of the present investigation the common red 

 spider is known to maintain itseK successfully on 183 species of wild 

 and cultivated plants, weeds, vines, bushes, and trees. A small 

 number of these hosts show special attractiveness for the pest and 

 infestation upon them reaches a more acute degree. These favorite 

 species may be grouped as winter hosts and summer hosts, the former 

 supporting th(^ pest through the cold, inactive period of the year, and 

 the liittcr funiisliing food thnjughout the spring and summer. 



