151 



gard to minimum amounts. We have been advising five or 

 six pounds of paste arsenate of lead, 15 per cent arsenic ox- 

 ide, to 100 gallons of water or its equivalent, though careful 

 spraying with four pounds to 100 gallons will control the 

 pest. The main point is the amount of poison deposited upon 

 the tree and not the amount in the spray mixture, though the 

 latter has a bearing upon the former. Spraying is not one of 

 the most costly of orchard operations and we would not ad- 

 vise a great reduction in either insecticides or fungicides, 

 though we recognize that a great dilution can be offset in 

 considerable measure by a very thorough and careful appli- 

 cation. Generally speaking our results will be proportional 

 to the thoroughness of distribution rather than to the amount 

 used per gallon. 



Arsenate of lime or arsenate of calcium is cheaper than 

 arsenate of lead and should be used on field crops rather 

 than in the orchard, largely because it has not been tested 

 out on fruit trees and there has been severe burning when 

 this poison was used on foliage without a lime preparation. 

 The danger of burning is considerably reduced by applying 

 the poison with a lime sulfur wash and almost entirely so, if 

 we may depend upon reports from the western states, if an 

 excess of recently slaked lime is present. It should not be 

 used on stonefruits. It is credited with possessing superior 

 adhesive properties as compared Mnth Paris green and since 

 it may be applied either dry or wet, it is an excellent poison 

 for potatoes. 



A word as to commercial insecticides may be pertinent. 

 A special committee on spraying materials reported at the 

 19th Annual Normal Institute for New York State Workers 

 as follows: "If, in conjunction with other weak fungicidal 

 and inseeticidal properties, we take into account the rela- 

 tively high prices of these materials, the evidence indicates 

 that these substances are not so efficient or economical as the 

 standard lead arsenate and bordeaux or arsenate of lead and 

 lime sulfur." Practically the same conclusions are voiced 

 as a result of experiments by the New Jersey, Virginia and 



