CHAPTER XVIII 



Fungicides combined with Poisons 



Materials that are used for the control of plant diseases, such as 

 scab, mildew, and the like, are called fungicides, as contrasted with 

 materials used for the destruction of insects, called insecticides. Fungi- 

 cides are not intended for the control of insect pests, and for the most 

 part have no value whatever in insect warfare. 



However, one of the materials commonly used for plant diseases, 

 Bordeaux mixture, has also some effect in driving away certain insects 

 from plants, or at least is distasteful to them. A second fungicide, 

 lime sulphur, as prepared for use in summer on trees in leaf, also has 

 some value as a mild contact insecticide, of considerable efficiency 

 against such soft-bodied sucking insects as plant lice. 



In addition, it is common practice to use either of these materials 

 with a poison, such as arsenate of lead, added to it, as a combined 

 insecticide and fungicide, instead of applying the two sprays sepa- 

 rately. Directions for their preparation and use, therefore, seem 

 proper at this point. 



Bordeaux Mixture 



Copper sulphate 4 pounds 



Lump lime 4 pounds 



Water 50 gallons 



Bordeaux mixture is a combination of copper sulphate, often known 

 as " blue vitriol " or " bluestone," with lime and water. It may be 

 bought in paste form, ready to dilute with water and apply; or it 

 may easily be made at home. 



To make Bordeaux mixture, place 25 gallons of water in a barrel, 

 and suspend in it, just below the surface, a cloth bag containing 4 



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