284 



THE MONTHLY BULLETIN. 



Fig, 61. — Lemon tree inoculated with a 

 pure culture of the Brown Rot Fungiis 

 November 23, 1912. Photogi-aphed May 6, 

 1913. The two narrow black lines to 

 the right are due to tar, not gum. run- 

 ning down from a limb above. (Paw- 

 cett, Monthly Bui. Cal. Hort. Com.) 



the infection has spread to any 

 great extent, much work and 

 money can be saved. Fawcett 

 also advises cutting back of the 

 top more or less severely, on 

 the side Avhere the bark has 

 been killed, provided the area is 

 large. 



The Bordeaux paste is made 

 by dissolving a pound of copper 

 sulphate in one gallon of water 

 in a wooden or earthen vessel, 

 two pounds of unslaked lime lime 

 in one gallon of water; stir to- 

 gether until cool. This makes a 

 light blue mixture about the con- 

 sistency of whitewash. The paste 

 deteriorates with age, so that 

 fresh mixture should be made 

 every day or so. Apply the paste 

 with a brush. 



Three or four inspections of a 

 grove a year are necessary to 

 discover the trees infected with 

 the gummosis before the disease 

 has spread to any considerable 

 extent, according to J. A. Prizer, 

 of the San Diego Fruit Com- 

 pany. The spread of the disease, 

 once the trees are infected, is 

 rapid, and control measures 

 should be prosecuted immediately 

 in order to check the disease be- 

 fore it has gained a foothold. 



Powdery Mildew of the Apple. 



This fungus attacks the leaves and shoots of the apple, characteristic 

 A\-hitish areas occurring most commonly on the undersides of the leaves. 

 Those affected with the mildew are dwarfed and distorted. Sometimes 

 the blossoms and young fruit are attacked. 



Spraying the trees Math iron sulfid is recommended by Ballard and 

 Volck, in Bulletin 120 of the U. S. Bureau of Plant Industry. Atomic 

 sulphur and milled sulphur are effective in controlling this disease. 

 The atomic sulphur can be obtained from the General Chemical Com- 

 pany of San Francisco, and is used at the rate of 7 pounds to 100 gallons 

 of water. The milled sulphur is manufactured by the California Spray 

 Chemical Company at Watsonville. 



Two sprayings may be necessary in order to eooitrol this disease, the 

 first being applied as soon as the fruit is set, the second three to four 

 weeks after the first. This spray can be combined with the arsenate 

 of lead spray for codling moth. 



