178 STATE HORTICULTURAL SOCIETY. 



DIRECTIONS FOR USING ARSENATE OP LEAD. 



Many expei-iments have sjhown that well-made arsenate of lead is 

 much the safest of all available arsenicals for use on the peach. Arsen- 

 ate of lead is to be found on the market both as a powder and as a putty- 

 like paste, which latter must be worked free in water before it is added 

 to the lime-sulphur mixture. The paste form of the poison isi larg-ely 

 used at the rate of about 2 pounds to each 50 gallons of the lime-sulphur 

 wash and is added, after it has been well Avorked free in water, to the 

 lime-sulphur spray previously prepared. As there are numerous brands 

 of arsenate of lead upon the market, the grower should be careful to 

 purchase from reliable firms. A decided change in color will result 

 when the arsenate of lead is added tO' the lime-sulphui' mixture, due to 

 certain chemical changes which, in the experience of the writers, do not 

 injuriously affect the fungicidal and insecticidal properties of the spray 

 or result in injury to the foliage. 



In large spraying operations it will be more convenient to prepare 

 in advance a stock mixture of arsenate of lead as follows: Place 100 

 pounds of arsenate of lead in a barrel, with sufficient water to work 

 into a thin paste, diluting finally with water to exactly 25 gallons. 

 When thoroughly stirred, each gallon of the stock solution will thus 

 contain 4 pounds of arsenate of lead, the amount necessary for 100 

 gallons of spray. In smaller spraying operations the proper quantity 

 of arsenate of lead may be weighed out as needed, and thinned with 

 water. In all cases the arsenate of lead solution should be strained 

 before or as it is poured into the spray tank. The necessary care should 

 be exercised to keep the poison out of the reach of domestic and other 

 animals. , i 



DANGER OF INJURY FROM SPRAYING. 



As stated elsewhere in this bulletin, the foliage of the peach is ex- 

 tremely sensitive to injury from such sjtrays as Bordeau mixture and 

 arsenicals, such as Paris green, arsenate of lead, etc. This sensitiveness 

 has been the sole reason why it has been impracticable to spray peach 

 orchards with fungicides and insecticides such as Bordeaux mixture or 

 Paris green, as has for years been the custom in the case of apples, 

 grapes, and other deciduous fruits. 



Of the various arsenicals available for use, well-made arsenate of lead 

 has proved to be the safest. Shortly after the development of this com- 

 paratively new insecticide, it was at once extensively experimented with 

 on peaches by numerous entomologists and it was tried to a limit extent 

 by peach growers. A single application of arsenate of lead in water did 

 not result in injury so important as to prevent its use. However, when 

 two or three applications were made, as is necessary in the control of 

 the curculio, serious shot-holing and falling of the leaves and even burn 

 ing of the fruit resulted, the latter in extreme cases, falling to the 

 ground. The use of lime with arsenate of lead lessened the danger of in- 

 jury considerably, but used even in this way for two or three treatments, 

 especially under certain weather conditions, resulted in extensive injury 

 to foliage and fruit. 



When it was established that the self-boiled lime-sulphur wash was 

 an effective fungicide and entirely safe as a spray for the peach, one of 

 the interesting questions presented was whether arsenate of lead might 



