19, 2 Lee: Citrus-canker Control 141 
Cresol-kerosene emulsion plus mercuric bichloride 1 to 1,500 
was used as an insecticide at the beginning of the experiment, 
to check the increase of scale insects. It was found that the ad- 
dition of bichloride to make a 1 to 1,500 solution was much 
too strong a mixture, and defoliation of many of the normal as 
well as cankered leaves resulted. The neutral Burgundy mix- 
ture was employed under greatly varying weather conditions; 
upon the citrus trees no evidence of burning of the foliage or 
fruit was ever observed in these experiments. 
The foregoing tabulation shows that a reduction in the 
amounts of citrus canker was obtained in this plat. The most 
noteworthy cases are those of the Kusaie limes and the trees 
of Citrus limonia, both of which species were reduced from a 
condition of fairly general infection to a condition of fairly 
satisfactory control. 
PLAT IV, AT LOS BANOS 
The treatment of this plat was as follows: 
August 24, 1917. Bordeaux 44-50 mixture plus sugar (sugar, 15 
per cent by weight of the copper sulphate in the mixture) and 
plus 1 quart of resin, sal-soda sticker. 
September 13, 1917. Bordeaux 44-50 mixture plus sugar (sugar, 
15 per cent by weight of the copper sulphate in the mixture) and 
plus 1 quart of resin, sal-soda sticker. 
October 11, 1917. Bordeaux 44-50 mixture plus sugar (sugar, 15 
per cent by weight of the copper sulphate in the mixture) and 
plus 1.25 quarts of resin, sal-soda sticker. 
November 12, 1917. Bordeaux 44-50 mixture plus sugar (sugar, 15 
per cent by weight of the copper sulphate in the mixture) and 
plus 1.25 quarts of resin, sal-soda sticker. To this was also 
added for this application powdered, neutral, lead arsenate to 
make a 1-50 mixture. 
December 20, 1917. Neutral Bordeaux mixture. 
January 3, 1918. Yothers’s oil emulsion. 
May 16, 1918. Neutral Bordeaux mixture plus formalin 1-100. ? 
June 14, 1918. Neutral Bordeaux mixture plus formalin 1-100 and 
cresol-kerosene emulsion. 
July 18, 1918. Neutral Bordeaux mixture. 
The use of sugar in Bordeaux mixture is described by Bour- 
cart(3) as having been first suggested by Perret. It was said 
to make the copper more easily available and to cause the Bor- 
deaux to adhere better to the foliage. Lutman(13) states that 
the addition of sugar to the lime before preparing Bordeaux 
mixture also weakens the precipitation membranes, causing the 
Precipitation to go more nearly to completion and increasing 
the covering power of the mixture. 
