602 THE MONTHLY BULLETIN. 



employed in preventing gummosis was due to the bringing about of con- 

 ditions that were unfavorable either to the infection by the causative 

 agents or to their development, or to both. These recognized methods 

 of prevention are important and can not be emphasized too strongly. 

 Keeping the soil away from the bud union, getting good drainage, using 

 sour orange stock for heavy soils, using high budded lemon trees planted 

 high for all new plantings, are important precautions that should not 

 be neglected. 



It remained true, however, that in spite of all the care that could be 

 exercised, certain cases of gummosis kept recurring, which appeared not 

 to be accounted for merely on the ground of unfavorable soil and cul- 

 tural conditions. "While the avoidance of these unfavorable soil and 

 cultural conditions was recognized by all growers as extremely important 

 in preventing the disease, and while the usual treatment of slitting and 

 painting with pure neat's-foot oil appeared to be successful in some 

 places, a number of growers felt that this treatment was inadequate, 

 and that the use of impure neat 's-foot oil had injured many trees. 



The writer had, while in Florida, with the help of Mr. 0. F. Burger, 

 proved that a gumming of orange and peach trees, accompanied by 

 killing of the bark and wood, was induced by a fungous growth, Diplodia 

 natalensis} On coming to California he was confronted with the ques- 

 tion as to whether fungi might not also play a part in gummosis of 

 lemon trees. It was well known that gumming took place in connection 

 with the attack of the peach blight fungus Coryneum beyerinkii.^ A 

 form of gumming of cherry trees in Oregon had recently been reported 

 as due to a bacterium.^ A number of fungi had been reported, also, as 

 causing gumming of peach, apricot and citrus trees in foreign countries. 



Professor Ralph E. Smith, at the Southern California Pathological 

 Laboratory, in talking the situation over with the writer, suggested that 

 further work be taken up on gummosis and other similar troubles, to 

 determine whether or not organisms had any relation to them. It was 

 for this reason and also because of the promise of hearty co-operation 

 by several growers that the work Avas first taken up in February, 1912.* 



'Mycologia III, 151-153; also Annual Report of the Florida Agricultural Experiment 

 Station for 1911, pp. 61-65, and same for 1912, pp. 77-Sl. 



=Smith, R. E., California Peach Blight, Bui. 191, California Experiment Station, 

 1907. 



'Griffin, F. L,., Science N. S. 34, p. 615, November, 1911 ; Barrs, H. P., Cherry Gum- 

 mosis. Biennial Crop Pest Report for 1911-1912, Oregon Agricultural Experiment 

 Station. 



*To Mr. J. D. Cultaertson, of the Limoneira Ranch, Mr. R. S. Vaile, County Horti- 

 cultural Commissioner of Ventura County, and to Mr. J. A. Prizer, of the San Diego 

 Fruit Company, is due the credit for having suggested and for having helped initiate 

 the experiments on which the results hereafter described are based. The success of 

 the work is also due to the hearty co-operation of Mr. C. C. Teague, of Santa Paula, 

 Mr. J. B. Boal, of National City, and Mr. L. B. Barnes of Chula Vista, who were 

 instrumental in furni.shing valuable trees and facilities for carrying on the work. 

 The Southern California Pathological Laboratory at Whittier, through Professor R. E. 

 Smith and his staff, aided and encouraged the work most generously by furnishing 

 room and allowing the use of valuable apparatus and other facilities. The Citrus 

 Experiment Station at Riverside, through Dr. J. E. Coit, also furnished a number of 

 trees for one series of inoculation experiments. Help was also given freely by many 

 others, especially by Mr. Milo Hunt, of Whittier, in furnishing a number of valuable 

 nursery trees for some of the experiments. Mr. John King, of Whittier, also fur- 

 nished a few citrus trees for one of the experiments. 



