THE WAR ON INSECTS 285 



effective there than it is on the Atlantic coast. A 

 variety of reasons for this difference have been sug- 

 gested, but for our purpose it is enough to recognize 

 that the fact exists. 



Sulphur by itself is not a mean insecticide if we 

 stretch the term insect just a little so as to include the 

 mites. In the greenhouse, against red-spider there is 

 nothing much better than flowers of sulphur dusted on 

 the surface, where the slow decomposition generates 

 fumes that are fatal to the mites and not conducive 

 to the multiplication of other parasitic organisms. 

 In the citrus orchards of Florida a similar practice is 

 adopted to prevent injury from the rust mite; lump or 

 ground sulphur is used, and here the hot, moist 

 atmosphere favors effects that are unobtainable in the 

 dry climate of the Pacific Coast regions. 



A barrel half full of lump sulphur set in a warm 

 comer of the greenhouse and kept filled with water is 

 an excellent spraying solution for general use on the 

 benches. There is very little sulphur in the solution, 

 but there is enough to keep down mites, check mildew 

 and destroy many other spores of disease organisms. 

 As the water is used, more is added, so that half a 

 barrel of sulphur may last a year or more. It needs a 

 warm corner to start decomposition. 



Combined in a soap, sulphur is used as a wash for 

 mangy animals, and as true mange is due to a mite, 

 good effects are obtained. Better yet are the results 

 when sulphur is administered internally. It is one 

 of- the materials eliminated through the skin, and is 

 therefore brought into direct contact with the skin 

 parasites. 



Among the penetrants the mineral oils rank highest. 

 A Hght crude petroleum of the paraffine series, testing 

 43° or over on the Beaume scale, will penetrate and 



