28 BULLETIN 500, U. S. DEPARTMENT OF AGRICULTURE, 



The codling moth, because of the long season and dry climate, is 

 very hard to control, especially in Mesa County, where conditions 

 for its rapid development are very favorable. In Delta County the 

 altitude is high enough and the climate moist enough to render the 

 moth much less troublesome; indeed, in some of the higher orchards 

 of this comity it is almost unknown. For this reason there is much 

 less spraying in Delta than in Mesa County. In Montrose County 

 none of the growers visited sprayed over three times for the moth, 

 the cost for that district falling even below that of Delta. 



Besides the codling moth sprays it is now the general practice, 

 enforced by law, to make a lime-sulphur spray for San Jose scale. 

 At the time these records were taken, however (1914), only a few 

 men sprayed for scale. Thus the cost of spraying for the region 

 has been very materially increased since the figures here presented 

 were obtained. 



Sprays are also occasionally made with tobacco extract for aphis. 



CODLING MOTH SPRAYS. 



In Mesa County the codling moth is impossible to control with 

 present methods without several sprays. Considering all records, 

 Mesa has an average of 5.28 sprays as against 3.16 for Delta County 

 and 2.73 for Montrose County. The first lead-arsenate spray is called 

 the calyx spray and is applied when about two-thirds of the petals 

 have fallen or before the calyx closes. The next spray follows in 

 about 10 days or 2 weeks. The dates of spraying always depend on 

 the relative time of blooming, weather conditions, and the relative 

 abundance of the moth. The grower uses his own judgment to a 

 great degree as to when and how often these sprays should be applied, 

 though he is guided to some extent by the inspection of the local 

 association or county agent. 



In each of the three counties .spraying in the bearing orchards is 

 done almost exclusively with a gasoline-power spray outfit. Thirty- 

 seven of the 49 growers in Mesa own spray rigs, while 12 hire the 

 spraying done. Of the 61 growers in Delta County 51 own and 10 

 hire. Of the 15 in Montrose all own except one, who hires. 



The customary spray mixture for codling moth is arsenate of lead 

 and water. Two kinds of lead arsenate are used, paste and dry. 

 As over 90 per cent used the paste lead arsenate, this will be con- 

 sidered here as the general practice. In Mesa County the lead 

 arsenate is mixed in the proportion of 8 pounds to 200 gallons of 

 water. In Delta County the average is 8.02 pounds to 200 gallons, 

 and in Montrose, 10.22 pounds to 200 gallons. The regular rate of 

 spraying labor is SI per hour for man, team, and rig. This figures 

 the man labor at 25 cents per hour, the team and rig at 75 cents. 





