^6 MAINE AGRICULTURAL EXPERIMENT STATION. I914. 



of tubers will not be diminished. At present such a treatment 

 can only be recommended as a rather extreme measure. 



Analyses for Poison oe Apples Sprayed with Arsenate oe 

 Lead in Mid-Summer. 



The brown-tail moth flight in July 19 13 was in the vicinity 

 c^f Highmoor Farm the heaviest that has been known. Though 

 all of the brown-tail moth nests were removed from the or- 

 chards at Highmoor Farm in the winter of 191.2-13, hundreds, 

 if not thousands, of nests must have been left in that vicinity. 

 The removal of brown-tail moth nests by picking is laborious 

 and expensive. It was, therefore, decided to thoroughly spray 

 the orchards after the female brown-tail moths had deposited 

 their eggs and at about the time when these eggs would be 

 hatching. Therefore, all of the trees in the orchard were 

 thoroughly sprayed with arsenate of lead the first week in 

 y\.ugust, 1913. The result, so far as the control of the brown- 

 tail moth was concerned, was a success, for in the winter of 

 1913-14 the orchards were free from brown-tail moth nests, 

 while all the unsprayed orchards in that vicinity, as well as the 

 many trees along the roadside, are literally covered with the 

 nests. 



It was with some trepidation as to the effect upon the crop 

 that arsenate of lead was applied so liberally when the apples 

 were a third grown. Arsenate of lead is a double dangerous 

 poison, not only because it contains arsenic but it also carries 

 lead which is a so-called cumulative poison. 



Therefore, at the time of harvest ten different lots of apples, 

 aggregating about two barrels of three different varieties, that 

 had been heavily sprayed, were pigked and sent to the labora- 

 tory. Care was taken in picking and handling so that any arse- 

 nate of lead which might be clinging to the apples should not 

 be removed. The apples in the ten lots were thoroughly and 

 carefully washed in water at the laboratory and all of the 

 washings saved. These were evaporated to the smallest 

 amounts possible and the organic matter removed. The deter- 

 minations of both the lead and the arsenic were made in 

 the washings from each lot, and the amounts of lead arsenate 

 present were calculated both from the lead found and from the 



