70 Report of State Board of Horticulture. 



with the lime-sulphur solutions as can the neutral arsenates. While 

 the available evidence upon the above points is not sufficient to 

 justify one in condemning the acid arsenates, growers are advised 

 to use neutral arsenates wherever possible. 



Most manufacturers advise the use of three pounds of arsenate 

 of lead to fifty gallons of water. The Washington Experiment 

 Station has demonstrated that in the dry climate of Eastern Wash- 

 ington one pound to fifty gallons gives equally good results in 

 controlling codling moth. We have found that two pounds are suf- 

 ficient in the Willamette Yalley. It is quite probable that one 

 pound may be sufficient here, but since this has not been demon- 

 strated we think it best to advise two pounds to fifty gallons for the 

 more humid portions of this State. 



Some gi'owers prefer to prepare the arsenate of lead as it is 

 used. This is but little if any more troublesome than to mix the 

 prepared arsenates in water and should be somewhat cheaper. It 

 can be readily prepared after the following formula: 



Arsenate of soda 4 ounces 



Acetate of lead 11 ounces 



Water 15 to 20 gallons 



Dissolve the arsenate of soda in two quarts and the acetate of 

 lead in four quarts of warm water. ^^Hien dissolved add them to 

 the required amount of water. 



This formula is especially valuable for spraying very delicate 

 foliage or for use against insects which are killed only by large 

 amounts of poison, since it can be used upon plants in much 

 stronger solutions than the other food poisons without injury to 

 the foliage. 



If it is desired to use a combined insecticide and fungicide, 

 arsenate of lead may be added to Bordeaux or to lime-sulphur solu- 

 tion in the same proportion as when water is used. 



bordeaux mixture. 



Bordeaux mixture has been the principal preventive of fungous 

 diseases. It is of some value as an insecticide, has a beneficial 

 effect upon plants independent of its effect upon their insect and 

 fungous parasites and may be used for most purposes in place of 

 water in the preparation of the arsenical sprays. 



Bordeaux for winter use may be made as follows : 



Copper sulphate 6 pounds 



Quick lime 6 pounds 



Water 50 gallons 



This is known as the 6-0-50 formula. It should be used only 

 upon dormant trees. When the trees are in leaf the following 

 4-6-50 formula is used: 



Copper sulphate 4 pounds 



Quick lime 6 pounds 



Water 50 gallons 



