357 
where most experimental work of this nature has been conducted. 
Methods applicable to the one region might be unsatisfactory in the 
other. It was desirable, also, that the work be done with the prune, 
which is not grown much in the East, and with which no experiments, 
as far as known, had been conducted. The line of treatment offering 
the greatest prospects of success was published by the writer early in 
the spring of 1892, so that those who desired might experiment in their 
own orchards.* 
Portions of two prune orchards, in which the rust had developed to 
a marked extent in 1891 were selected for the experiment. The orchards 
were about 5 miles apart, one south of Santa Ana and the other east 
of Orange, Oal. The trees in one orchard were sprayed with modified 
eau celeste, while a portion of those in the other orchard were sprayed 
with modified eau celeste and a portion with ammoniacal copper car¬ 
bonate. The number of treatments and time of application were varied 
with different lots of trees. Besides these, two other orchards in the 
vicinity of Santa Ana were sprayed by their owners, both gentlemen 
using the modified eau celeste according to the formula followed in our 
work. One of the orchards, belonging to Mr. Charles Leslie, is sit¬ 
uated northwest of Santa Ana, on ground somewhat lower than that of 
any of the other orchards treated. 
Fortunately for the growers, but unfortunately for our experiments, 
the rust did not develop as early, and was not as general nor as 
virulent in the season of 1892 as in 1891. The disease did develop, 
however, in the orchard of Mr. Leslie, though later than usual and 
with less virulence. Here a striking contrast was observed between 
the treated and untreated trees about the 1st of October, qjid we are 
now able to show the efficacy of the spray used and to give the details 
and necessary expense of application. 
In relation to the application of sprays, it may be said that for young 
trees of small size and pruned low, the knapsack sprayer may some¬ 
times be used to advantage. This is especially true of gardens and 
orchards of small extent. Treatment of small trees with a knapsack 
sprayer will require from one and one-half to three minutes per tree, 
according to size and state of development of the foilage. The tank of 
the sprayer holds about 4 gallons, and to avoid loss of time some con¬ 
venient mode of refilling should be near at hand in the field. For trees 
4 or 5 years old a cart sprayer holding one or two barrels of the spray¬ 
ing mixture is very convenient. Experiments were conducted with 
the a Little Giant” cart, holding slightly over a barrel. The tank is 
* See notes on “Fungous diseases and tlieir treatment.”<Troc. and Trans, ot the 
Pomological Soc. of Southern California, Redlands, May 27 and 28, 1892, pp. 24-29; 
also, Rural Californian, June, 1892, pp. 303-305, and extracts in numerous other 
journals. The present season’s work has shown that the disease mav he controlled 
with fewer sprayings and at less expense than were thought necessary at the time 
these recommendations were made. 
