Feb., 1926] PROGRESS OF AGRICULTURAL EXPERIMENTS 33 



Table XX — -Yield in quarts of sirawberries per one-twentieth acre plot 



to copper injury such as the apple and peach. In previous experiments 

 0. Butler has found that on plants not sensitive to copper neutral Bor- 

 deaux mixtures were less injurious than alkaline mixtures, the standard 

 •4-4-50 Bordeaux mixture for instance; on the other hand, on plants 

 sensitive to copper increasing the alkalinity of the mixture was in general 

 beneficial, more especially in the matter of protection to the older leaves. 

 During the past year he has studied the effect of increasing the lime to 

 five times the copper sulphate present, and has found that injury is 

 ver}^ nearly if not entirely prevented. Bordeaux mixtures containing 

 as much lime as copper sulphate will cause injury when a Bordeaux 

 mixture containing five times as much lime as copper sulphate will be 

 without injurious effect. 



Toxicity of Fungicides to Parasitic Fungi (Adams Fund) 



Experiments were made by L. J. Klotz with arsenious oxide, hydrated 

 lime in aqueous suspension, barium tetrapsulphide and ammoniacal 

 silver chloride. Ammoniacal silver chloride was most active of the 

 fungicides used, and was toxic at a strength of .00625 per cent to the 

 spores of Alternaria solaiii which germinate readily in most of the fungi- 

 cides in common use. 



Apple Scab {Hatch Fund) 



Experience having shown that apples can be adequately protected, 

 even under conditions favorable for scab infection, by spraying at the 

 pre-pink, pink and calyx stages and that the 1 4-day s-after-the-calyx 

 application was not materiall}^ beneficial, L. J. Klotz has been investi- 

 gating the increase in area exposed to infection from one spraying to 

 another. To facilitate calculations the fruit was assumed to be round, 

 and determinations were made on Grimes' Golden, Mcintosh, Baldwin, 

 Ben Davis, etc. In general it may be said that the surface area increases 

 on the average from the pre-pink to the pink stage 2.31 mm.; from the 

 pink to the calyx stage 4.3 mm., and from the calyx to 14-day s-after-the- 

 calyx stage 94.32 mm. The data obtained, therefore, confirm the results 

 of the spraying experiments; for if infection occurred as readily after the 

 calyx spray as before, the spray interval would be too wide to give pro- 

 tection. 



