CONCLUSIONS, COLLEGE PARK, MD. 15 



trees had begun a new growth and the leaves developed a darker 

 color. 



The slight injury to the apple trees of the month before was not 

 noticeable, both those sprayed with and without lime being in good 

 condition. 



The peaches were located on a dry knoll and accordingly had suf- 

 fered most from the drought, but at this observation, after having 

 dropped their affected leaves and put forth new ones, both series of 

 the trees had so far recuperated as to show scarcely any effect from 

 the Paris Green, the foliage being nearly as thick as upon unsprayed 

 trees. 



The plum trees, while showing more injury^ than the peaches, were 

 decidedly improved. 



The last examination was made on August 8, and as far as could be 

 ascertained the trees of all varieties had completely recovered from 

 the effects of the various sprays. 



CONCLUSIONS. 



The effect of these Paris Greens, both with and without lime, upon 

 the apple trees was very slight, and, as far as could be estimated, the 

 same may be said of the pears. 



To the peach trees considerable temporary injury, as shown by a drop- 

 ping of the leaves, was done b} 7 all the greens without lime, although 

 the trees seemed to recover later in the season. With lime the peaches 

 were not injured to any great extent, even temporarily, by greens 

 Nos. 1, 2, and 3 (2.84, 4, and 5 per cent of arsenious oxid), but were 

 injured temporarily to quite an extent by greens Nos. 4, 5, and 6 (6, 

 Y, and 8 per cent of arsenious oxid). All of the trees, however, seemed 

 to recover before the end of the season. An interesting point noted 

 in the case of the peach trees was that no injury was noticeable until a 

 month after the application of the spray, the delay in action being 

 probably due to the absence of rain. 



Another fact emphasized by the observations was that the injury 

 always depended to a considerable extent upon the physical condition 

 of the individual tree; in a number of cases a particularly vigorous 

 specimen showing no injur} 7 , while its less thrifty neighbor, which 

 was perhaps sprayed with a Paris Green containing less soluble 

 arsenious oxid, was seriously damaged. 



From the results of this work it is believed that apple and probably 

 pear trees can be sprayed ^vith Paris Green containing 8 per cent of 

 soluble arsenious oxid and sustain no injury. The observations made 

 on peach and plum trees tend to show that if lime is added Paris Green 

 containing as high as 5 per cent of free arsenious oxid may be safely 

 used. 



