1 1 8 INSECTS AFFECTING THE ORANGE. 



same time 40 to 50 per cent, of the molting Mites died. On the third 

 day many molting Mites remained alive. Eggs not killed. 



The above solution of sulphuretted hydrogen (sulphur water) was pre- 

 pared by passing through two gallons of water, the gas given off by 

 three ounces of sulphuret of iron, treated with dilute sulphuric acid.* 



The remarkable results obtained with sulphur in these experiments, 

 and especially the effect of the gas in solution upon the adult Mites, sug- 

 gests the use of water from the sulphur springs which abound in various 

 parts of Florida. Although it cannot be supposed that these natural 

 waters contain a sufficiently high percentage of the mineral to render 

 them powerful insecticides, their value cannot be determined without 

 trial. Persistent applications may suffice to ultimately exterminate the 

 Bust- mite or cause its disappearance from the trees. In view of its pos- 

 sible importance as a remedy, those who have access to natural springs 

 or who now use flowing wells of sulphur water for the purpose of irriga- 

 tion, should thoroughly test it by making repeated applications at short 

 intervals. 



Kerosene. Emulsions containing 66 per cent, of kerosene oil, and 

 diluted with water ten times, as in applications for Scale-insects, do not 

 kill the eggs of the Rust-mite. The same emulsions, diluted one to 

 twenty, kill nearly all the mites, but do not kill the eggs. With dila- 

 tions of one to forty, many adults escape destruction. En all the ex 

 periments made with kerosene upon Scale-insects the trees were not 

 cleared of Rust-mites. They usually reappeared in numbers, within 

 five or six days, owing to the hatching of the eggs. As a remedy for 

 Rust-mite, therefore, kerosene is not as effective as either whale-oil soap 

 or sulphur. 



In making applications for Scale-insect it is advisable to render the 

 wash effective against Rust-mite also, and this can be in a measure ac- 

 complished by adding sulphur. 



Experience has shown whale-oil soap to be superior to condensed milk 

 in forming emulsions, and much cheaper. Emulsions made with soap 

 do not thicken or ferment, as when milk is used. 



The formula given in the preceding chapter (see ante, page 94) gives 

 the best results. 



The emulsion should be diluted with water ten times, or in the propor- 

 tions 1 to 9, and applied in fine spray. 



In cases where an application is needed for both Scale-insect and Rust- 

 mite the above wash, with two or three ounces of sulphur added to each 

 gallon of the mixture, forms the most effective combination that can at 

 present be devised. It is best applied in early spring, but should never 

 be used in midwinter or when there is danger from frost. 



Carbolic Acid. Several experiments with crude Carbolic acid, saponi- 

 fied with lard oil and lye, or dissolved in strongly alkaline solutions, 



*A solution of sulphuretted hydrogen may be very simply prepared by boiling sul- 

 phur in lime-water. (See Sulphurated Lime, ante, p. 98.) 



