-38- 



13. June 2d, an orchard of many varieties, including Bavay, 

 was sprayed with one pound London purple to 200 gallons. No 

 harm resulted. 



14. July 3d, a lot of plum trees, comprising Coe's Golden Drop, 

 German Prune, and Bavay, were treated with the colored liquid 

 which stood above a London purple mixture of one pound to 400 

 gallons for 15 hours. (Lot 6 was treated with this material). No 

 injun' was done. 



A careless observer would have said that the plums were in- 

 jured, as many of the leaves were spotted and often perforated. 

 But these injuries were entirely fungous (in this case, apparently 

 due to 'Phyllosticta pyrina), and were easily distinguished from 



Fig. 5. — Plum Leaf Injured by Fungus. 

 poison injuries. Fig. 5 shows one of these leaves ; it should be 

 compared with Fig. 3, and the entire absence of the scalded, 

 blotched and curled appearances noted. 



We do not discourage the general use of London purple, as we 

 use it freely upon other plants than the peach. 



SUMMARY. 



1. Peach trees are very susceptible to injury from arsenical 

 sprays. 



2. London purple is much more harmful to peach trees than 

 Paris green, and it should never be used upon them in any manner. 



3. Injury is more liable to occur upon full grown foliage and 

 hardened shoots than upon young foliage and soft shoots. 



4. The immunity of the young growth is due to its waxy cov- 

 ering. 



5. Injury late in the season is more apparent than early in the 

 season, because of the cessation of growth. 



