355 
was properly ripened. Both the general and special effects of the dis¬ 
ease vary according to the situation of the orchard, the age and variety 
of stock, the soil, etc. 
When it attacks the prune the parasite causes the upper surface of 
the leaf to turn a yellowish or reddish color in irregular blotches, of 
greater or less extent, according as the points of attack are separate or 
confluent. The spores make their appearance in brownish or blackish 
patches on the under surface of the leaf, the brown patches usually 
being made up of uredospores and the black of teleutospores. The 
uredospores often appear earlier in the season than the teleutospores, 
the latter being normally developed as winter spores. Both kinds of 
spores are of good size and well formed. When the rust is abundant 
the tissue of the lower portion of the leaf is destroyed in such a manner 
as to present continuous, brown, lifeless areas. With the Tragedy 
prune, grown on the place of Mr. D. Edson Smith, of Santa Ana, the 
tissue of the under surface of the leaves was entirely destroyed, and 
was covered by an almost continuous and very dense layer of spores. 
The action of the rust on the plum is similar to its action on the 
prune. In Texas it is stated that wild plums are attacked. Both 
uredospores and teleutospores are found, the latter often predomina¬ 
ting. 
Peach trees are frequently badly affected by this rust, and the trees 
of an entire orchard are sometimes defoliated. On the upper surface of 
the leaves the infected parts become yellowish or reddish in irregular 
and somewhat angular blotches, and on their under surface in separate 
or confluent, yellowish or brown, somewhat circular spots. The spores 
are mostly uredospores, although the teleutospores are often found, at 
least in California.* The fungus lives over winter on the tender twigs 
of the peach, frequently almost killing the young nursery stock. For 
this reason it would be well to spray the trees during the dormant 
season as well as after the growth has begun. For this winter treat¬ 
ment the following mixture is recommended: 5 pounds of copper sul¬ 
phate, 10 pounds of lime, and 45 gallons of water. 
The extra amount of lime causes the fungicide to adhere better than 
the usual amount of o pounds in ordinary Bordeaux mixture. It is not 
positively known if the same holds good with the prune and plum, 
although it is probable. Where rust is very bad upon either of these 
fruits the winter treatment is recommended. 
On the nectarine the rust produces both uredospores and teleuto¬ 
spores, but, as with the peach, the uredospores greatly predominate. 
*In the Animal Report of the Commissioner of Agriculture for 1887, pp. 353-354, 
it is said that no teleutospores are developed on the peach. Although less abundant 
than the uredo form, they have invariably been found on badly infected peach leaves 
in southern California, and these leaves have been obtained from widely separated 
points in Los Angeles and Orange Counties, as at Florence, Santa Ana, Arch Beach, 
etc. They were fully matured by the middle ot October. 
