70 FUMIGATION INVESTIGATIONS IN CALIFORNIA. 



Page. 



Fumigation against citrus scales, improved system 58-68 



advantages 63-64 



apparatus 53-61 



dosage schedule 64-67 



in use 67-68 



procedure 61-63 



supply cart 59-61 



method of computing dosage and volume for 



tented trees 25-26 



methods for obtaining measurements and dos- 

 age of trees with and without apparatus. . . . 26-30 



present system, apparatus 18-19 



dosage schedules 19-24 



procedure 18-19 



procedure in improved system 61-63 



present system 18-19 



proportion of materials used by fumigators 32-39 



simplification by improved system 68 



sulphuric acid, amount necessary 32-34 



effect of too great an excess. . . 34 



jar and cover 60-61 



removal from drums and car- 

 boys 53-55 



supply cart 59-60 



. table to replace supply cart on very rough 



ground 61, 62 



tents, marking for estimating dosage. . . 27-30, 55-56 



sheet 17-18 



time of year 48-52 



tray for canying chemicals in present system. . 18-19 



water as a factor 34-35 



correct proportion 38-39 



effect of different proportions on tem- 

 perature and amount of available gas. 35-38 



while fruit is small 51-52 



purple scale 40-46 



length of exposure 44-45 



preliminary experiments 40-43 



generators, cover 56-58 



Fungus, black, or sooty-mold, on citrus trees infested with black scale 15 



Honeydew, secretion by black scale 15 



Hydrocyanic-acid gas. (See also Fumigation.) 



in drums 55 



Icerya purchasi, enemy of citrus fruits 11 



Insects, beneficial, used against citrus scales in California 16 



Kerosene-water spray against citrus scales 17 



Lemon. (See Citrus.) 



Lepidosaphes beckii. (See Scale, purple.) 



Mealy bugs, distribution in California 14 



enemies of citrus fruits 11 



Mite, rust, of orange. (See Phyllocoptes oleivorus and Mite, silver, of lemon.) 

 silver, of lemon. (See also Phyllocoptes oleivorus.) 



sulphur spray as remedy 16 



