ACTION OF LEAD ARSENATE ON FOLIAGE. 



41 



TABLE IX. Comparison of monthly meteorological data for 1908 with the average 



for thirty-eight years. 



SUMMARY FOR 1908. 



The results on the apple trees were the same as in 1907, that is, 

 the foliage was not injured in any case from applications of pure lead 

 arsenate or any of the by-products naturally formed in its manu- 

 facture. 



Rather severe injury was caused to the foliage and fruit of the 

 peach by pure lead arsenate, made either from lead acetate or lead 

 nitrate, and the same was true when the salts formed as by-products 

 in the making were not washed out, whether applied with or without 

 lime. The fruit was of a deep red color which generally extended 

 throughout the flesh, and maturity was hastened about one week. 



Lead nitrate caused severe injury to the foliage but not to the 

 fruit. Lead acetate in the stronger application caused slight injury 

 to the foliage, but very materially protected the fruit from insect 

 injury. Sodium acetate and acetic acid, acetic acid alone, and 

 sodium nitrate produced no injurious effect on the foliage or fruit 

 in the strengths applied. 



The meteorological conditions from March to August, 1908, were 

 very different from those for the same period in 1907. In general 

 the temperature was considerably above the normal, and the rain- 

 fall was very much below normal except for May and August. One-half 

 of the total rainfall for May (nearly as much as the normal average 

 for the month) fell on two consecutive days. During June and most 

 of July the rainfall was very light. No injury from previous spray- 

 ing could be detected on May 25, when the final application was 

 made. Five hot, clear days, without rain, followed this application, 

 and on June 4, ten days after the application, very decided injury 

 was observed. From the appearance of the foliage the injury would 

 probably have been noticeable several days previously, but no obser- 



