18 



purchasing such machinery may be reduced by two or three planters 

 buying one machine for their common use. By the use of geared 

 machinery from 20 to 30 acres of cotton may be dusted in the few 

 hours suitable for the work. In order to secure good results the 

 plants should be dusted while still wet from dew or a light shower, as 

 the moisture aids in retaining the fine particles of poison upon the 

 foliage. 



Three pounds of Paris green should be applied per acre and where 

 large machines are used economy may be practiced by mixing the 

 poison with from three to four times the amount of cheap flour or 

 fine, air-slaked lime. In spraying, the poison sliould be used at the 

 rate of 1 pound to 50 gallons of water. Owing to the variability in 

 strength of poisons only reliable brands should be purchased. 



The decided prejudice on the part of many planters and pickers 

 against the application of poison is entirely unfounded, for no danger 

 attends its proper use either in the application or in picking cotton in 

 fields which have been treated. 



TRAP CROPS. 



As has been stated, corn is the preferred food of bollworm larvae 

 and nectar secreted by cowpeas is very attractive to the moths. From 

 a consideration of these facts it is perfectly natural to conclude that 

 by proper manipulation these may be made to form a trap for the boll- 

 worm and thus protect cotton or other crops from injury. 



The best results may be secured by leaving several unplanted strips, 

 from 60 to 80 feet wide, across the fields at the time of planting 

 cotton. These strips should later be planted to corn and cowpeas in 

 alternate rows about 3 feet apart at a time which will permit of the 

 corn being in silk and tassel and the peas in bloom by August 1, the 

 approximate date of the emergence of the majority of third genera- 

 tion moths. The early corn being then about ripe the moths are im- 

 mediately attracted to the trap rows. The cowpeas afford food and 

 hiding places for the moths and corn is the favorite plant for oviposi- 

 tion ; the moths are therefore content to remain in the trap rows and 

 here their eggs are concentrated, thus leaving the adjacent cotton 

 practically free. 



The accompanying table gives some idea of the number of eggs 

 kept from surrounding cotton fields by the employment of a small 

 area of June corn as a trap crop. These observations were made 

 during 1905 at Ardmore, Ind. T., on a small area of corn which was 

 in prime silking condition on August 1. At the time of the first 

 examination the corn was in full silk and when the second examina- 

 tion was made the silks were largely dry and some corn in roasting 

 ears. The figures show the average number of eggs per plant and 



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