VEGETABLE PARASITES AND WEEDS 181 



The copper sulfate alone is so caustic that it will " burn " 

 the plants, but the lime largely neutralizes this caustic 

 action. If the lime is good, the above formula supplies 

 it in excess and insures neutralization. If, however, the 

 lime is poor or one is in doubt, there are certain tests which 

 may be applied. 



If much spraying is to be done, it is convenient to make 

 up considerable quantities of " stock solutions " of each 

 of the ingredients, copper sulfate and lime. These are 

 best made to contain one pound of the chemical in each 

 gallon of water. These solutions may be kept indefinitely 

 by simply guarding against evaporation. 



The arsenical compounds (283) may be added to the 

 bordeaux mixture and thus a single treatment serves for 

 both insects and fungi. 



331. Ammoniacal solution of copper carbonate pos- 

 sesses nearly the same fungicidal properties as bordeaux 

 mixture, but adheres less strongly to foliage. Being a 

 solution, it requires no straining or stirring, and it leaves 

 less stain on drying than bordeaux mixture, which makes 

 it preferable to the latter for use upon plants of which 

 the fruit is nearly mature. To make this solution, dis- 

 solve one and one-half ounces of precipitated copper 

 carbonate in one quart of strong commercial ammonia, 

 and add 25 gallons of water. The ammonia should be 

 procured in a glass or earthen vessel, which should be kept 

 tightly corked. To prevent waste of the ammonia by 

 evaporation, prepare immediately before spraying. 



332. Lime sulfur (295) is also employed extensively 

 for the control of fungous diseases. Greater dilution 

 is practiced for fungous diseases than when this mate- 

 rial is used as an insecticide. At one part lime sulfur 

 to thirty or thirty-five of water applications can be 



