19 



In reply to an inquiry for further information upon this subject Miss 

 South worth wrote me as follows, under date of November 2, 1889 : 



I think the fungus which I found on the orange scale is a Capnodium, although 

 there is an unusual absence of effused mycelium, the spores appearing to be borne 

 mainly on upright conidiophores. It is in the conidial stage and no pycnidia or 

 perithecia are present. It is accordingly impossible to be certain of the species, 

 although I incline to the belief that it is C. citri. This species has now, however, 

 been changed to Meliola citri. 



I do not think I stated positively that I found the fungus on living scales. I found 

 it sparingly on Red Scales, but I could not be sure they were living. 



The fungus referred to as Capnodium citri is the same kind that 

 causes the " black-smut n on citrus and other kinds of trees, and is sup- 

 posed to draw its nourishment from the excretions of various kinds of 

 insects that feed upon the sap of these trees. It seems very probable, 

 therefore, that this fungus would also attack the liviug insects them- 

 selves, although, as Miss Southworth states, we can not say positively 

 that such is really the case. 



But, notwithstanding the great number of these scale-insects that 

 annually fall a prey to their various insect enemies, and the thousands 

 that perish from some cause as yet not clearly understood, still these 

 pests manage to multiply at an astonishingly rapid rate, making it 

 necessary for owners of infested trees to employ artificial means in 

 order to save their trees from utter destruction. 



One of the most successful remedies ever used for the destruction of 

 the Eed Scale on citrus trees is the treatment with hydrocyanic acid 

 gas, first used by the writer in the autumn of 1886. As I gave a full 

 account of this treatment in my annual report for the year 1890, pub- 

 lished in Bulletin No. 23, Division of Entomology of this Department, 

 (pp. 20 to 27) it will be needless to more than refer to it in this con- 

 nection. 



Among the different kinds of washes that have been used for the de- 

 struction of these scales, the one giving the best results is known as the 

 resin wash, and is fully described in my annual report for the year 1889, 

 published in Bulletin No. 22 of this Division (pp. 10 to 17). This wash, 

 while it does not destroy as large a percentage of the Eed Scale as the 

 gas treatment, still is fatal to the Red Spider (Tetranychus sp.) and also 

 to the eggs of the Black Scale (Lecanium olece Bern.), both of which 

 are frequently found on the same* trees as the Eed Scales, and neither 

 the Eed Spider nor the eggs of the Black Scale are destroyed to any 

 great extent by the gas. For these reasons some of our fruit-growers 

 have adopted the method of using the gas treatment and the resin 

 wash alternately, first spraying the infested trees with the wash in July 

 or August, which destroys the greater portion of the Eed Spiders and 

 Black Scales, as well as a large percentage of the Eed Scales. Then in 

 November or December the trees are treated with the gas, which pretty 

 thoroughly completes the destruction of the noxious insects infesting 



