10 PARIS GREEN SPRAYING EXPERIMENTS. 



not injured to a great extent, but a few leaven fell. The injury to trees 

 when lime was used with the Paris Green was not nearly so great as 

 when lime was not used, which was to be expected. Those sprayed 

 with solutions Nos. 1, 2, and 3 (4.29, 5, and 6 per cent of arsenious 

 oxid), with lime, while showing a slight yellowing, spotting, and fall- 

 ing of the leaves, were not injured to any great extent, and the falling 

 of the leaves soon cea,sed. All of the sprayed peach trees lost their 

 leaves much earlier in the autumn than is common in and around 

 Washington; but as all of the trees near by had been used in the experi- 

 ment it was not possible to make any comparison with unsprayed trees 

 to ascertain whether the premature ripening of the leaves was due to 

 some other cause than the poison. 



The apple trees when sprayed with varying strengths of arsenious 

 oxid, without lime, all showed about 1 to 2 per cent of injury. A few 

 leaves were curled and burned at the edges where the Paris Green had 

 collected in the greatest quantities, but the injury was slight, and after 

 these leaves fell the trees did not show that they had been sprayed at 

 all. All were in good condition and remained so throughout the sum- 

 mer, except the one sprayed with solution No. 1, which died during 

 August. 



The same results were obtained on the trees sprayed with the various 

 solutions after the addition of lime. None was seriously injured, and 

 in about two weeks after the spraying no effects could be seen. In 

 the case of the tree sprayed with solution No. 2, with lime, it was 

 observed that about one-third of the leaves had fallen on September 18, 

 but as the trees sprayed with much stronger solutions were in no way 

 affected it appeared that the dropping of the leaves was not caused by 

 the spray. It was noted in the case of trees sprayed both with and 

 without lime that about one-half of them lost the greater part of their 

 leaves by October 12, which is rather early in this climate. This was 

 not true to so great an extent of the trees that had been sprayed with 

 the addition of lime, but still there was a tendency in this direction. 

 Four extremel} 7 hardy apple trees, sprayed with solutions Nos. 3 and 

 4 (6 and 7 per cent arsenious oxid), with lime, did not drop their leaves 

 early, while two trees, not so hardy, that were sprayed with solutions 

 Nos. 1 and 2 (4.29 and 5 per cent arsenious oxid) dropped over one- 

 half of their leaves by October 12. It did not appear that the prema- 

 ture dropping of the leaves in the autumn was accompanied by any 

 permanent injury to the tree. 



The pear trees, in those cases in which no lime was used, had a few 

 leaves burned on the edges at the first and second observations, but 

 these soon dropped off or withered away, and the trees were in excellent 

 condition. In fact, it may be said that pear trees sprayed with any of 

 the five solutions without lime were practically unaffected, none being 

 damaged to the extent of 2 per cent. The trees sprayed with any one 

 of the solutions with lime were not scorched in the slightest degree. 



