8 Maine; agricultural experiment station. 1914. 



evident that the amount of scab on the leaves of the trees on 

 this plot was considerably less than on the unsprayed check 

 but it was also equally apparent that it was more than on the 

 adjoining plot, sprayed with the larger amount of arsenate of 

 lead, and more than on the plots sprayed with fungicides plus 

 the same amount of arsenate as was used on it. 



The only evidence of spray injury observed was a slight spot- 

 ting of the leaves and this in all cases appeared to be associated 

 with areas of leaf surface where the epidermis had first been 

 attacked by the scab fungus, allowing the poison to come in 

 contact with the interior tissues. 



On plot 9, sprayed with 2 pounds Oif dry arsenate of lead in 

 50 gallons of water, the control of scab on the leaves through- 

 out the season appeared to be fully equal to that where standard 

 dilution lime-sulphur and the smaller quantity of arsenate had 

 been used together. 



Some spotting of the leaves was observed similar to that 

 described on plot 8, but up to the middle of August this was of 

 no consequence. After this date the farm was visited less fre- 

 quently and less detailed records were kept as to the condition 

 of the foliage. At harvest time it was discovered that more 

 or less spotting of the leaves had developed late in the season 

 and that there had been a slight amount of premature leaf fall. 

 However it may be said that the general health of the foliage 

 on the trees on this plot throughout the season as a whole 

 compared favorably with that on the lime-sulphur plots. 



Plot 10, standard dilution lime-sulphur plus one pound of 

 arsenite of zinc to 50 gallons. This plot was introduced simply 

 to secure additional data as to the combined effect of arsenite 

 of zinc and lime-sulphur on apple foliage. In 1912 this combi- 

 nation gave no appreciable spray injury but in 19 13, used in 

 exactly the same manner, in the same proportions, and from 

 the same stock of arsenite of zinc a decidedly opposite result 

 was obtained. This year severe leaf injury resulted. The 

 character, amount and time of appearance of this was almost 

 identical with that produced by ''Soluble sulphur" already 

 described. The specimens shown in Pig. 2 were collected 

 on July 7. 



