28 LEAD ARSENATE. 



Experiment 8. To observe the effect of lead acetate on foliage to determine whether, 

 if lead acetate were added in considerable excess, it would cause burning. Applied 

 in the proportion of 2.7 ounces to 50 gallons of water. (This is 10 per cent of the theo- 

 retical amount of lead acetate required to make 1 pounds of dry lead arsenate.) 



Experiment 9. To determine whether a still larger excess of lead acetate would 

 burn when applied in the proportion of 5.4 ounces to 50 gallons of water. (This is 

 20 per cent of the amount required to make 1J pounds of dry lead arsenate.) 



Experiment 10. To prove whether a small excess of lead nitrate would cause burning 

 when applied in the proportion of 2.1 ounces to 50 gallons. (This is 10 per cent of the 

 theoretical amount of lead nitrate required to make 1J pounds of dry lead arsenate.) 



Experiment 11. Same as Experiment 10, except that the material was applied at 

 the rate of 4.2 ounces to 50 gallons, which is 20 per cent of the theoretical amount of 

 lead nitrate required to make 1J pounds of dry lead arsenate. 



A number of trees were left unsprayed in different portions of the 

 orchard for comparison. The -spraying was done on the following 

 dates: April 18, first application on peach A and B, Experiments 1 to 

 7, inclusive. The following day it rained, and on April 20 the appli- 

 cation was made according to Experiments 8 to 11, inclusive. The 

 foliage on the apple trees had not developed sufficiently at this date 

 to be sprayed. The second application was made on peach A and B 

 and the first application on apple A and B on April 29 and 30. April 



29 applied the spray in Experiments 1 to 9, inclusive, and on April 30 

 in Experiments 10 and 11. On May 13 and 14 the third application 

 was made on peach B and the second application on apple A and B. 

 On May 13 applied spray in Experiments 1 to 4, inclusive, and 

 finished on the following day. The third application on apple B was 

 made on June 4. 



RECORD OF OBSERVATIONS. 



Observations were made on the condition of the foliage at intervals 

 of one to two weeks, and a detailed record kept which it is not neces- 

 sary to record here in full. It may be stated in the first place in 

 regard to the apple that no noticeable injury whatever was caused to 

 the foliage from any of the various mixtures, either in the case of 

 two or three applications. The following notes apply only to the 

 peach: 



June 4. On this date the last spraying was done and no evidence of any injury to 

 the foliage was apparent which could be attributed to the materials previously ap- 

 plied. A number of leaves showed split and ragged edges, but this was no doubt 

 caused by a severe hailstorm which occurred on May 19. No scorching or burning 

 of the foliage was noticeable. 



June 28. The foliage showed no injury except that on the trees in Experiment 11B, 

 which had been sprayed three times with the stronger solution of lead nitrate. This 

 showed some spotting and the "shot hole" effect, though the injury was not serious. 

 The amount of fruit on these trees was small, many of them did not have any at all, 

 and, owing to the unfavorable weather conditions which had prevailed during the 

 growing season, the fruit was all of inferior quality; however, that on the unsprayed 

 trees was in a worse condition than on those to which lead ar;-enate had been applied. 



July 19. As far as the foliage was concerned, very little injury was apparent which 

 could be attributed to the spraying mixtures. Experiment 3B showed slight leaf in- 



