Insects and Fungi Attacking Trees, Etc. 347 



used only in a dilute form, i to i gallon of the solution to 

 50 gallons of water, according to the kind of trees to be 

 sprayed. To the above solutions may be added arsenate 

 of lead 4 to 6 lbs. to 50 gallons of the mixture for the 

 destruction of insect pests. 



Leaf-blights. — The leaf-blights are unlike the rusts in 

 that they attack and destroy small portions of the leaves, 

 and when these spots or places of attack become numerous 

 the whole leaf is destroyed and it soon falls off. Among 

 the most destructive of the leaf-blights are the Catalpa- 

 LEAF Spot {Phyllosticfa catalpce), Cherry- and Plum- 

 leaf Blight {Cylindrosporiiim Fadi), Maple-leaf Spot 

 {Phyllostida acericolor), Sycamore-leaf Blight {GI(eo- 

 sporium nervisequtun), Rose-leaf Spot {Adinoncma rosce), 

 etc. 



Remedy. — As ^^^th the rusts, the copper must be on the 

 plants to destroy the spores when they come in contact with 

 it, but when the parasite has become fully established nothing 

 Tvill destroy it that will not destroy the host plant. The 

 treatment is the same as for the rusts. 



Mildews or White Rusts. — As the name indicates, 

 these are parasites which produce white spores and more or 

 less white patches on the leaf or other parts. As with the 

 two pre™usly named groups, they grow under conditions 

 of moisture and hot, moist weather, and as a rule they appear 

 later in the season. 



Among the most destructive of this group are the Rose- 

 mildew {Sphcerotheca pannosa), Powdery ^Mildew of 

 the Hawthorn, Plum, and Cherry {Podosphcera oxy- 

 canthcB), Downy ■Mildew of the Willow {Uncinula 

 salicis), Dow^NY Mildew of the Lilac {Micros phcEra 

 Alni D. C), etc. 



Remedy. — Coming on later in the season than the brown 

 rusts, two or three appHcations with the Bordeaux mixture 



