■ ORCHARD SPRAYING EXPERIMENTS. 53 



some fungicidal value, both laboratory and field tests indicating 

 increased efficiency of the sulphur sprays when lead arsenate is 

 added. 



The effect of carbonic acid gas, used in a gas sprayer, is 

 worthy of note. With lime-sulphur solutions alone the re- 

 action of the gas was not of a nature to produce injurious re- 

 sults. Such reaction where lime-sulphur v/as used with lead* 

 arsenate did result in injury to peach foliage. The results ob- 

 tained by Wallace do not warrant him in recommending the use 

 of a gas sprayer in applying these materials when combinel. 



The addition of lime to lime-sulphur solutions gave no con- 

 clusive results. Laboratory tests indicated increased fungicidal 

 powers by the addition of iron sulphate to the lime-sulphur ; the 

 use of the two combined with lead arsenate was less effective 

 than when the iron sulphate was omitted. 



Experiments at Highmoor Farm, Maine Agricueturae 

 Experiment Station, 1910. 



The increasing evidence of spray injury and the results of the 

 preceding season in the orchards at Highmoor Farm made it 

 desirable to test out the lime-sulphur sprays as substitutes for 

 bordeaux mixture in this State. 



The experiment aimed at determining the following points : 



1. The comparative efficiency of the lime-sulphur sprays and 

 bordeaux mixture as fungicides, especially for apple scab. 



2. A comparison of these sprays in regard to possible injury 

 to foliage and fruit on a variety especially susceptible to spray 

 injury — the Ben Davis. 



3. The effectiveness of arsenate of lead in combination with 

 lime-sulphur solutions. 



4. The relation of possible leaf and fruit injury to the com- 

 bination of sulphur sprays with lead arsenate. 



The experiments as originally planned included a study of 

 arsenic in other forms combined with the sulphur sprays and a 

 trial of the latter without arsenicals. The number and condition 

 of trees available this season for such a study made it necessary 

 to confine it to the points aforementioned. These cover the really 

 important questions in the lime-sulphur problem. It is, after 

 all, of very secondary importance whether or not lime-sulphur 



