SELECTING AND PREPARING MATERIALS 



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Commercial forms of Bordeaux, both paste and powder, are 

 available. In general, these are not so desirable as the freshly 

 made material. They do not adhere so well to the fruit and 

 foliage, are usually less effective as fungicides, and their cost 

 is considerably in excess of that of the home-made prepara- 

 tion. The commercial forms are useful for the home garden 

 where small amounts are required. 



Bordeaux mixture combined with lead arsenate is also 

 available commercially as a fungicide and insecticide. Deter- 

 mine from the analysis the amount of water-soluble arsenic. 

 It should not exceed % of 1 percent, or severe burning may 

 follow its use. Use the preparation at such strengths as to 

 give the standard applications of both materials. 



b : 3. Sulfur used alone in dust form is a good fungicide. 

 It seldom causes, burning. It should be at least 98 percent 

 pure, and the particles should pass through a 300-mesh sieve 

 (300 meshes per inch, 90,000 per square inch). Fineness of 

 division adds much to its adhesiveness and consequent effec- 

 tiveness, and coarse dusts should never be used. 



Sulfur dust alone, or in combination with powdered lead 

 arsenate and lime dust, is used quite extensively for the sum- 

 mer control program on apples, pears, peaches, and cherries. 



b : 4. Wettable sulfurs possess fungicidal value. They 

 are mixtures of sulfur with a flux which makes them compat- 

 ible with water. Dextrin, flour, glue, and calcium caseinate 

 are some of the materials with which the sulfur is mixed. 

 Flotation sulfur paste is a good example of this type of 

 fungicide. Although each manufacturer gives his own direc- 

 tions, usually the diluted spray should contain from 6 to 8 

 pounds of actual sulfur in 50 gallons of water and if used in 

 conjunction with arsenicals about 2 to 4 pounds of lime to 

 each pound of arsenical. This type of fungicide is much 

 easier on foliage than lime-sulfur. Not only is it unlikely to 

 cause burning, but also it allows the tree to develop larger 

 and more healthy foliage. In other words, it exerts no in- 



