53 



can be overcome. Somewhat to our surprise it has been demon- 

 strated that this material (20 per cent mechanical emulsion) can be 

 applied to peach trees in midsummer without material injury beyond 

 dropping foliage in places where it is exceptionally thick. This 

 heroic measure was adopted in the case of a very badly infested 

 orchard ; and an application of this character is certainly preferable 

 to allowing the scale to breed with very little or no check. 



Experiments with many lime-sulphur combinations were inaugu- 

 rated last spring for the purpose of testing, in a practical way, the 

 value of different proportions of ingredients and also of a more or less 

 prolonged boil. Two formula} in particular were tested ; the 30-30-30 

 combination to 100 gallons, and the 40-15-20 to 60 gallons. The 

 former gives a smoother wash with very little sediment, and its insec- 

 ticidal value is most excellent. The latter wash has considerable 

 more sediment and forms more of a coating upon treated trees. It 

 was just as destructive to the scale as the preceding, so far as our 

 observations went. A modification consisting of 25 pounds of lime 

 and 20 pounds of sulphur to 60 gallons of water was tried, and in our 

 own experience was fully as desirable as either of the others. It 

 contained a little more sediment than when equal proportions of lime 

 and sulphur are used and not so much as where twice as much lime 

 as sulphur is employed. Tests to determine the value of salt led us 

 to the conclusion, taken in connection with the results obtained by 

 others, that it had comparatively little value, and we therefore omit- 

 ted it from our formula. The prolonged boiling insisted upon in so 

 many formulae was reduced in some cases to but thirty minutes, and we 

 found that where lime was slaked in a kettle of hot water and the 

 sulphur added at the beginning of the operation, thirty minutes' active 

 boiling gave a wash just as efficient as though it had been boiled two 

 hours. Consequently we are at present recommending a lime-sulphur 

 wash composed of 25 pounds of lime and 20 of sulphur to 60 gallons of 

 water; slake the lime in a few gallons of hot water in a kettle, add 

 the sulphur at once, boil actively for thirty minutes, and dilute to the 

 required amount, preferably with warm water, though no ill effects 

 seem to follow the use of cold water. We also tested the utility of 

 employing a resin adhesive made by dissolving 3 pounds of sal soda 

 in 3 quarts of water and adding thereto 4 pounds of resin and boiling 

 until it was dissolved. This was diluted to 5 gallons and then added 

 to the lime-sulphur wash. We found that the wash must be moder- 

 ately warm or the resin solution is apt to cause coagulation and thus 

 produce a mixture which might clog the pump seriously. This wash 

 undoubtedly adhered a little better than where the resin was not 

 employed, though in practical field work we could see no decided 

 advantage from the addition of the resin. 



Observations in a large apple orchard at Poughkeepsie, which has 

 been infested with San Jose scale for thirteen years, have proved to 



