402 Diseases of Greenhouse Crops 



one standard fungicide. The term as employed here, 

 however, refers to any effective fungicide that is 

 best adapted to each particular case. For instance, 

 Bordeaux mixture may be termed "standard" if used 

 to spray greenhouse muskmelons or cucumbers. In 

 this case the staining of the Bordeaux would not 

 injure the marketable product since the Bordeaux 

 film may be readily washed or wiped off. However, 

 Bordeaux mixture could not be termed standard 

 for spraying roses in bloom. At that time the Bor- 

 deaux stain may injure the market value of the 

 bloom more than would the disease that we wish 

 to control. In this case, therefore, ammoniacal cop- 

 per carbonate or some other colorless fungicide may 

 be termed standard. 



Bordeaux Mixtures. The strength used for ten- 

 der plants is three poimds of copper sulphate — ^also 

 known as blue stone, six pounds of lime, and fifty 

 gallons of water. The easiest way to prepare it is 

 to dissolve the blue stone thoroughly in twenty-five 

 gallons of water. The best quality of unslaked 

 lime should be used and slaked in a little water, care 

 being taken, however, not to flood it while slaking, 

 nor to let it become too dry. When the slaking is 

 completed, enough water is added to make twenty- 

 five gallons. The lime water and the blue stone so- 

 lution are then mixed, pouring in first one part of 

 lime water, then another part of the blue stone; the 

 mixture is then strained and used at once. 



For crops with less delicate foliage, the standard 

 Bordeaux mixture is 4-4-50; that is, four pounds 



