COST OF PRODUCING APPLES IN YAKIMA VALLEY. 45 



LEAD-ARSENATE SPRAYS. 



Usually three or four lead-arsenate sprays are made for the control 

 of the codling moth. Some growers find it necessary to make as 

 many as six sprays. Throughout the valley there is considerable 

 variation in the time that the calyx spray is applied. This is due 

 primarily to differences in altitude and season. In 1913 it was 

 applied between April 22 and 27; in 1914, April 20 and 25; in 1915, 

 April 25 and 30; and in 1916, April 27 and May 2. Lead-arsenate 

 paste is used by the majority of orchardists for these sprays. From 

 1J to 3 pounds of this paste is used in 50 gallons of water. 



The calyx or first lead-arsenate spray. — The calyx spray is considered 

 by the majority of orchardists to be the most important. All make 

 it about the time that 75 to 90 per cent of the petals have fallen. 

 By referring to Table XXXIV it will be seen that the same number 

 of owned and hired outfits were used in this spray as in the dormant 

 spray. The former averaged about an acre less in 10 hours and 

 applied about 90 gallons per acre more than the latter, making a 

 total labor and material cost of $1.18 more per acre for those who 

 own outfits than those who hire. More material is usually applied 

 per tree in this spray than in any of the others, at least by the better 

 class of commercial growers. The total labor and material cost 

 per acre for the calyx spray in the North Yakima district (55 orchards) 

 was $4.24, while in the Zillah district (50 orchards) it was $4.77. 

 Considering all records, whatever size of crew or whether the spray 

 outfit is owned or hired, the total labor and material cost per acre 

 for the calyx spray was $4.47, or 17.78 per cent of the total labor 

 and material spraying cost. (See Table XXXVI.) 



Second lead-arsenate spray. — The second lead-arsenate spray is 

 usually made from three to four weeks after the calyx spray. The 

 date of application will vary with the season. It is usually between 

 the 11th and the 25th of May, but sometimes as late as the first of 

 June. The purpose is to poison the codling-moth larva?, which are 

 beginning to hatch at this time. This spray was made by 78 per 

 cent of the growers considered in this investigation. As in the former 

 sprays, it will be seen that the cost per acre for labor and material is 

 greater for those who own their outfits than those who hire, and that 

 more of the orchardists in the North Yakima district hire their spray- 

 ing done. The total labor and material cost for the North Yakima 

 district (45 orchards) was $3.64 per acre; while in the Zillah district 

 (37 orchards) it was $4.57. Considering all records, regardless of crew 

 or whether the spray outfit is owned or hired, the total labor and 

 material cost per acre for the second lead-arsenate spray was $3.09, 

 or 12.29 per cent of the total labor and material spraying cost. (See 

 Table XXXVI.) 



