620 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



The best oils for spraying purposes have a viscosity of about 300 

 to 400 and they may be purchased from any of the oil companies 

 operating in the citrus-growing belt. Petroleum fuel oil and 

 distillate or gas oil may also be used and when applied should be 

 used at twice the strength indicated for the lubricating oils. 

 The soaps may be purchased from any grocery or fertilizer 

 company. 



Proprietary Miscible Oils. 



"There are several proprietary miscible oils on the market 

 which the writer has found to give highly satisfactory results. 

 These should be diluted so that the spray material will contain 

 somewhere between ^ per cent and 1 per cent of oil. The writer 

 would advise the use of oil emulsions when diluted to about 1 

 per cent. Experience indicates that such substances as rosin 

 oil and sulphuric acid should not be used in proprietary 

 insecticides." 



Use of Fungus Diseases. A method for the control of some 

 citrus insects, particularly the whiteflies, in Florida, is the artificial 

 dissemination of fungus spores causing certain fungus diseases 

 to which these insects are susceptible. The discussion of the 

 fungi and methods used is included with the discussion of the 

 whiteflies as this method is not so extensively used for other 

 insects. 



There are, however, four * principal fungus parasites or dis- 

 eases, of scales that are at times very effective in the natural 

 control of citrus scales in Florida and the Gulf Coast. These are 

 the Red-headed Scale-fungus (Sphaerostible coccophila Tul) the 

 White-headed Scale fungus (Ophionectra coccicola E. & E.), the 

 Black Scale fungus (Myriangium duriaei Mont), and the Pink 

 Scale fungus (M icrocera fujikuroi Miyabe & Sawada). 



The first of these infects and kills the purple scale, long scale and 

 chaff scale and several scales infesting deciduous trees, including 

 the San Jose; the second infects the purple scale and long scale; 

 the third the purple scale, chaff scale, long scale and San Jose Scale; 

 the fourth the Florida red scale and purple scale. 



* See P. H. Rolfs and H. S. Fawcett, Bulletin 119 (Revision of 94). Fla. 

 Exp. Sta. for the first three fungi named herewith. See J. R. Watson, Report 

 of Entomologist, Annual Report 394, Fla. Exp. Sta. for the 4th or pink scale 

 fungus. 



