580 CALIFORNIA FRUITS: HOW TO GROW THEM 



and causing the leaf to fall. These fungi are only slightly, if at all, 

 checked by the dry sulphur treatment, and are best subdued by the 

 use of copper solutions : 



The Bordeaux Mixture. Lime, four pounds; bluestone (sulphate of cop- 

 per), four pounds; water, forty gallons. Use part of the water to slake the 

 line and dissolve the bluestone, which should be done in separate vessels. The 

 bluestone should not be put in a metal vessel. If put into a bag and sus- 

 pended near the surface of the water, it will dissolve more readily, or hot 

 water may be used in making the solution. Both should be cold when mixed, 

 and the resultant mixture will be a beautiful blue wash. If mixed hot, a black 

 compound (copper oxide) is produced, which reduces the value of the wash. 

 After thorough mixing of the solutions, water should be added to bring the 

 bulk up to forty gallons. 



This is safe to use on foliage. It may be used much stronger 

 when trees are dormant as strong as ten pounds of lime and ten 

 pounds of bluestone to forty gallons of water to kill spores of fungi 

 on the bark, but the chief advantage of the stronger mixture is not 

 directly in spore-killing but in the longer resistance to removal by 

 rains. This winter treatment is a successful preventive of curl-leaf 

 on the peach, shot-hole on the apricot, scab on the apple and pear, 

 rust on the prune, etc. In the case of the peach blight, which is an 

 invasion of the young bark by the shot-hole fungus, an autumn 

 spraying is imperative to protect the dormant twigs.* When the 

 fungus survives winter treatment or when it attacks the fruit, as in 

 case of the apricot particularly, or the leaf in the peach, there should 

 follow the weaker Bordeaux in the spring or summer, as early as 

 indications of the diseases may appear. In spraying for apple and 

 pear scab, the addition of five pounds of lead arsenate to each one 

 hundred gallons of the Bordeaux Mixture makes the application 

 answer also for the codlin moth, as described in the preceding 

 chapter. 



When it is desirable to use a fungicide on fruit near the picking 

 season, or on ornamental plants, which would be disfigured with 

 the lime wash, the ammonical copper carbonate may be submitted 

 for the Bordeaux Mixture, viz. : Copper carbonate, four ounces ; 

 ammonia, forty ounces ; water forty gallons. 



The usual way of making this wash is to dissolve copper carbon- 

 ate in ammonia, and then dilute. If the carbonate is not fully dis- 

 solved before the water is added, it can not be further dissolved, and 

 not only is the carbonate wasted, but the fluid will not be up to 

 standard strength. It is well, therefore, to give the ammonia ample 

 time to act, say over night, before adding the water. 



The lime, salt and sulphur mixture, as already prescribed for 

 scale insects in the preceding chapter, is an active fungicide for 



"Consult Bulletin 191 of the University Experiment Station on "California Peach 

 Blight." 



