112 Maine Agricultural Experiment Station. 1918. 



In order to obtain as much light as possible upon the com- 

 position of this material certain definite questions regarding 

 this point were asked of the manufacturers. The following is 

 quoted from a statement made by their chemist : 



"The T. P. product will contain about 3% to 5% PbHAs0 4 . 

 The remaining As,0 5 and PbO are combined as either a mix- 

 ture of Pb 3 (As0 4 ) 2 and some new basic arsenate, or entirely as 

 the new basic arsenate, the composition of which, as far as the 

 writer knows, has not been definitely determined." 



The writer farther stated that while he was not familiar 

 with the article of Robinson and Tartar that this new basic ar- 

 senate probably corresponds with the one they described. 



Time and Manner of Spray Applications in 1917. 



The dates of application in 19 17 were May 30, June 20 and 

 July 9, which shows a very abnormal situation. Previous to 

 this the latest date for making the so-called "pink-bud" applica- 

 tion, during 7 consecutive seasons, was May 24, and the earliest 

 May 8. In the same period the second date, as determined by 

 the fall of the petals, has been quite constant, usually not earlier 

 than the third and not later than the sixth of June. 



The method of application was the same as in 191 6 except 

 that a pressure of 200 pounds was constantly maintained by the 

 spray pump. 



Conditions During and Following the Spraying Season 



of 1917. 



The entire growing season, on the whole, was uncommon- 

 ly cold, cloudy and wet. The very slow development of the 

 flowers, and consequent delayed spray applications, was due 

 to unseasonably cold, wet weather. Between the first and second 

 applications of spray something over 9 inches of rainfall was 

 recorded at the farm. On account of a leak which developed 

 in the rain gage it was impossible to get an accurate record of 

 the rainfall for June, but as near as could be determined it 

 was over 10 inches. The observer estimates that over 4 inches 

 fell in a single storm, June 10-12. The combined rainfall for 

 May and June was about 12 inches. These conditions made it 

 extremelv difficult to control scab effectively. 



