38 BULLETIN 518, U. S. DEPARTMENT OF AGRICULTURE. 



Bordeaux 4-4^50 solution — that is, 4 pounds of lime, 4 pounds of 

 blue vitriol, and 50 gallons of water. The lead arsenate is used the 

 same strength as above. In all cases growers use arsenate of lead 

 in this spray for the control of the codling-moth larva, although 

 some omit the other ingredients. Where either Bordeaux or lime- 

 sulphur is used it is for the control of apple scab. Some growers now 

 make a practice of using about 3 pounds of atomic sulphur to 50 

 gallons of spray mixture for apple powdery mildew, and apply it in 

 combination with the calyx spray. 



Whatever mixture is used, the number of acres sprayed per day 

 is between 5 and 6. Cost for labor is $1.47 per acre for diluted 

 lime-sulphur and lead-ar senate spray, $1.50 for Bordeaux and lead 

 arsenate, and $1.54 for lead-arsenate spray alone. The material cost 

 for these sprays is $1.48, $2.41, and $0.75, respectively, or a total 

 labor and material cost of $2.95, $3.91, and $2.29. (See Table XIV.) 

 The lead arsenate and water spray is thus the cheapest, followed 

 by the lime-sulphur and lead arsenate, and, lastly, the Bordeaux 

 and lead arsenate, which is much the most expensive. In this 

 calyx spray the most popular and, judging by the number using it, 

 evidently the most effective combination is the lime-sulphur and 

 lead-arsenate spray. If mildew is troublesome, atomic sulphur may 

 be added. 



The next lead-arsenate spray follows the calyx application in 

 about 10 days. It is made by only a part of the growers. If the 

 weather is favorable to apple scab, lime-sulphur, diluted 1 to 40 

 or 1 to 50, or atomic sulphur, 5 pounds to 50 gallons, is often added 

 to this lead-arsenate spray. Some growers do not put lead arsenate 

 in this spray, but use only the lime : sulphur or atomic sulphur. 



The " thirty-day " spray is usually the second and a very essential 

 spray for the control of codling moth. This occurs about 30 days 

 after the calyx spray, hence its name. Lead arsenate at the rate of 

 2 pounds to 50 gallons is used. Atomic sulphur may be added at 

 the rate of 5 or 6 pounds to 50 gallons for scab and mildew control. 



Other sprays for scab control are sometimes applied if the weather 

 continues wet, and ordinarily the third and last lead-arsenate spray 

 for the codling moth is applied about the 1st of August. However, 

 there may be an intervening codling-moth spray between the thirty- 

 day spray and the final spray for the moth. In this spray lead 

 arsenate is applied at the usual rate of 2 pounds to 50 gallons of 

 water. Bordeaux 1 1 50 may be combined with this as a further 

 protection against scab. In many of these sprays, particularly the 

 early ones, a nicotine solution is often added for the control of the 

 aphis, at the rate of about 1^ pints to 200 gallons of spray mixture. 



