372 INSECTS AFFECTING VEGETATION 



Sulphur. Flowers of sulphur is one of the best remedies for 

 plant mites, such as the red spider, the six-spotted orange mite, and 

 the rust mite of citrus fruits. It may be applied in several forms, the 

 simplest of which is its use as a dry powder dusted over the trees with 

 powder bellows or any broadcasting device, preferably in the early 

 morning when the foliage is damp with dew, or immediately after a 

 rain. For the rust mite in very moist climates, such as that of Flor- 

 ida, to keep the fruit bright it is sufficient merely to sprinkle the 

 sulphur about under the trees. The flowers of sulphur may be easily 

 applied also with any other insecticide, such as kerosene emulsion, 

 resin wash, or a soap wash, mixing it up first into a paste and then 

 adding it to the spray tank at a rate of from 1 to 2 pounds to 50 

 gallons. Somewhat more uniform results can be obtained perhaps 

 by getting the sulphur into solution, either dissolving it with lye or 

 by boiling it with lime. (Farmers' Bui. 127, U. S. Dep. of Agr.) 



In making the lye-sulphur wash, first mix 20 pounds of flowers 

 of sulphur into a paste with cold water, then add 10 pounds of pul- 

 verized caustic soda (98 per cent). The dissolving lye will boil and 

 liquefy the sulphur. Water must be added from time to time to pre- 

 vent burning, until a concentrated solution of 20 gallons is obtained. 

 Two gallons of this is sufficient for 50 gallons of spray, giving a 

 strength of 2 pounds of sulphur and 1 of lye to 50 gallons of water. 

 An even stronger application can be made without danger to the 

 foliage. This mixture can also be used in combination with other 

 insecticides. 



The chemical combination of sulphur and lime known as sul- 

 phid of lime is perhaps a better liquid sulphur solution than the last 

 as a remedy for mites. It may be very cheaply prepared by boiling 

 together for an hour or more, in a small quantity of water, equal 

 parts of flowers of sulphur and stone lime. A convenient quantity 

 is prepared by taking 5 pounds of sulphur and 5 of lime and boiling 

 in 3 or 4 gallons of water until the ingredients combine, forming a 

 brownish liquid. This may be diluted to make 100 gallons of spray. 



Almost any of the insecticides with which the sulphur may be 

 applied will kill the leaf of rust mites, but the advantage of the 

 sulphur arises from the fact that it forms an adhering coating on the 

 leaves and kills the young mites coming from the eggs, which are 

 very resistant to the action of insecticides. 



Petroleum Oils. The emulsions of kerosene, or coal oil, with 

 soap or milk have long been the standard insecticides for external 

 sucking insects, and especially the aphides and scale insects, and 

 these emulsions still are the safest and most reliable means of get- 

 ting these oils upon plants. 



In addition to its direct application to plants, kerosene is often 

 used as a means of destroying insects by jarring the latter from 

 plants into pans of water on which a little of the oil is floating, or by 

 jarring them upon cloths or screens saturated with kerosene, prefer- 

 ably the crude oil. The same principle is illustrated in some of the 

 hopper-dozers, or machines for collecting grasshoppers and leaf- 

 hoppers. 



