l8 MAINE AGRICULTURAL EXPERIMENT STATION. I912. 



applied with the carbonic acid gas sprayer, as in the work of 

 the past season. 



On the contrary, no such effect was noted at Highmoor or 

 in one of the cooperative experiments where a like sprayer and 

 the same ingredients were used. In the present state of knowl- 

 edge we may therefore admit the possible presence of soluble 

 arsenic in the lime-sulphur-lead arsenate combination and still 

 suggest as a plausible explanation of calyx or similar injuries 

 the strength of such soluble arsenic in relation to the health of 

 the tree, as indicated by its physiological resistance expressed 

 in the apple tissues at time of spraying. 



Effectiveness in Fungus Control. No conclusions can prop- 

 erly be made from this season's work, either in regard to the 

 relative efTectiveness of the several lime-sulphur sprays in 

 various dilutions or the comparative efficienc}' of them and 

 bordeaux mixture. The cause of this is the unusually hot, dry 

 summer, preceded by a very warm dry spring. Under condi- 

 tions such as these the spores of fungi parasitic to the apple 

 could neither germinate to any degree nor make much growth 

 after germination. This is shown by the presence of only one 

 scaibby apple in the entire experiment. 



For the fruit grower such a season adverse to the dissemina- 

 tion and propagation of fungi is a great boon. To the worker 

 in experiments with fungicides the contrary is true, for with- 

 out the presence of parasites in considerable amount the experi- 

 ment fails utterly in this respect. 



Fungicidal Efficiency of Lead Arsenate. The explanation 

 just given holds here for lack of data on this point. Work of 

 this nature must be repeated until a sufficient number of sea- 

 sons with conditions favorable for the accumulation of experi- 

 mental data have passed. In this respect the work of 1911 well 

 demonstrates the futihty of making well defined deductions 

 from the results of one or a few years' work. 



Relation of Russcting to Linie-Sidphur. Nothing in the 

 results of this year indicates any relation between the small 

 amount of russeting found on the several plots and the nature 

 of the spray applied. The table of results shows that the plot 

 sprayed with lime-sulphur at dilution-table strength yielded 

 practically the same percent of russeted apples as the plot 

 sprayed with a strength 20 percent stronger than the table 



