19, 2 Lee: Citrus-canker Control 187 
rows of native sweet oranges, calamondins, lemons, Kusaie 
limes, citrons, and pummelos. With the exception of the Kusaie 
limes, these trees are largly native to the Philippines, without 
classification into horticultural varieties. The trees were, for 
the most part, five years old at the beginning of the experiment, 
and although varying considerably in size were commonly 3 to 
5 meters in height and, with a few exceptions, in good growing 
condition. The trees were in orchard formation upon level land, 
protected but partially from the strong and sometimes violent 
winds. The orchard was clean cultivated at all times of the 
year; no irrigation was practiced during the dry season. 
The orchard was divided into six plats, so arranged that each 
plat cut across the rows of similar species at right angles; each 
species was thus represented in each plat. It may seem unfor- 
tunate that the experiments were not carried on in, orchards of 
a single uniform susceptible species, having plats consisting of 
but one variety; however, this was impossible in as much as no 
such mature orchard existed at that time in the Philippines. 
The use of the specific name Citrus maxima (C. grandis, C. 
decumana) as pointed out by Merrill(15) has been followed in 
this paper. 
PLAT I, AT LOS BANOS 
The treatment of this plat consisted of an application of lime 
sulphur (32° Baumé) in a 1 to 40 solution. It was found that 
lime sulphur washed off very easily during the heavy rains at 
Los Bafios.* In as much as the rains are normally very heavy 
in the wet season in Los Bajos, it was apparent that lime 
sulphur could not be used against canker in this locality and its 
use on this plat was, therefore, abandoned. 
PLAT II, AT LOS BANOS 
Plat II consisted of two rows running parallel with rows of 
Plats I, III, IV, V, VI, and was left entirely untreated as a 
check upon the rows that were treated. The amounts of canker 
*In this connection various methods were attempted to cause lime sul- 
phur to adhere to the foliage for a longer period. Powdered casein in the 
ratio of 4 ounces to 50 gallons was sifted into the solution; compared with 
an application of lime sulphur without casein, made at the same time, no 
advantage was gained. Casein in the form of condensed milk was added 
to lime sulphur and similarly gave no advantage. The resin salsoda 
sticker was added in the ratio of 1 quart to 50 gallons of the lime sulphur. 
This mixture was applied to a plat of trees while at the same time lime 
sulphur with no such sticker was applied to a similar plat of, trees. The 
foliage of both plats tested for sulphur at the end of two weeks was en- | 
tirely negative. 
