INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 171 



REPELLENTS 



It is apparent that certain materials, applied to the foliage ot 

 plants, are somewhat repulsive to some insects. One of the most 

 important of these repellents is the well known fungicide, Bordeaux 

 mixture. Because of this and its use as a combined insecticide and 

 fungicide the formula and directions for making are'here presented 

 quite fully. 



BORDEAUX MIXTURE 



Uuslaked lime 4 pounds 



Copper sulphate (Milestone) 4 pounds 



Water 50 gallons 



The task of mixing these chemicals, where large cpiantities of the 

 spray is used, is no small thing in itself. A great deal of study has 

 been given to the construction of suitable mixing apparatus. 



The first consideration is to get the materials high enough on a 

 platform so that they can be easily and rapidly placed in the spraying 

 tanks of the power machines. This is done by constructing at con- 

 venient places in the orchard platforms large enough to hold a large 

 box for slaking lime, a lime solution agitator, and a vat for dissolving 

 the bluestone. Such a platform is about 12 feet square and 44 feet 

 high. A large standpipe for filling the tanks is desirable or the 

 water must be pumped into the tank while the solutions are being 

 added. 



The lime is first slaked in a common vat for that purpose. The 

 great trouble has always been to keep the slaked lime agitated prop- 

 erly when it was being drawn off to mix with the bluestone in the 

 spraying tank. This problem has been solved by the use of a special 

 agitator for this purpose. The lime from the slaking vat is strained 

 into this tank through the slanting bottomed strainer. The agitator 

 works by means of a hand lever and the contents of tin 1 tank may be 

 thoroughly mixed in a few minutes before it is drawn off for use. 

 Here it is again strained through the strainer as is also the bluestone. 



The bluestone vat has slats, across the entire box, or simply across 

 one end. These slats must be low enough so that the bluestone. which 

 is placed upon them in sacks, will be completely immersed in the 

 water. This method admits quick dissolving of the bluestone. much 

 more rapidly than if simply poured into the tank and stirred. 



The lime and bluestone are mixed with a given amount of water so 

 that the proper quantities of the resultant solutions can he measured 

 so as to give the mixture the strength of the above formula. 



The sieve used should he made of brass wire and contain twenty 

 meshes to the inch. 



This spray is usually used as a repellent for the flea-beetles, cucum- 

 ber beetles," diabrotica, and other leaf-eating insects. 



Bordeaux mixture may he used in combination with Paris green, 

 lead arsenate (acid and neutral), calcium arsenite and in some instances 

 with rosin soap for special purposes, but should not he combined with 

 tobacco or used prior to fumigation. 



::-js 



