FUNGOUS DISEASES 351 



plant depending upon the number and vigor of the 

 parasite or robber plant that is f eeding^ upon its tissues. 

 The amount of injury done in a season will depend 

 upon, first, the condition of the weather — little or no 

 injury being done in cool, dry weather, while in warm, 

 moist weather this class of plants are sure to develop 

 rapidly; and second, upon the vigor and strength of the 

 host plant to resist the attack of the parasites. 



FUNGICIDES 



Any substance that will destroy or prevent the 

 growth of a fungus is called a fungicide, or fungus 

 killer, and in the growth of all of our farm and garden 

 crops it has become a necessity to use fungicides as 

 well as insecticides, and the fruit grower must equip 

 himself with apparatus for this work just as much as 

 with tools for cultivation if he would insure his crops. 



As explained under the treatment for insect pests, 

 so with fungous pests the fruit grower must depend 

 upon his local experiment station for full and detailed 

 instruction as to preventive measures, appliances, and 

 applying fungicides, but a brief description of the 

 fungicides in most common use may not be out of place 

 in this volume. 



Copper Sulphate — This substance has become an 

 almost universal fungicide and is most used in a mix- 

 ture with lime known as the bordeaux mixture. 

 Standard bordeaux mixture is made up of four pounds 

 copper sulphate, four pounds caustic lime and fifty 

 gallons of water. But where the fruit is in a condition 

 to be disfigured by it, it is used as a weak solution of 

 copper sulphate alone. The bordeaux mixture is found 

 in the market already prepared for use and under 

 various names, and many of them have some value, 

 especially where the amount of spraying is small and the 



