l80 MAINE AGRICULTURAL EXPERIMENT STATION. I916. 



plot 4. It hardly seems possible that the calyx tubes could have 

 been injured sufficiently at the time of spraying with the strong 

 lime-sulphur to account for all of the russeting experienced. 



From a practical standpoint it is evident that bordeaux mix- 

 ture cannot be safely used on the Ben Davis, even for the 

 first spray application before the blossom buds open. On the 

 other hand it is equally evident from the experience of several 

 seasons that the amount of lime-sulphur concentrate in a given 

 amount of spray used for this first application may be increased 

 20 per cent without fear of appreciable leaf injury or of in- 

 creasing russeting. It will be noted that there was less rus- 

 seted fruit ®n plot 3, sprayed in this manner, than there was on 

 the unsprayed check. In this respect it agreed with plot 5 

 which had arsenate of lead alone for all 3 applications. 



Late Application of Dormant Strength Lime-sulphur. 



It seems improbable that an application of dormant strength 

 lime-sulphur would be of material benefit in controlling apple 

 scab except in cases of the over-wintering of the fungus on 

 young twigs. This, however, in Maine according to the writer's 

 observations is confined to the Mcintosh and a few other varie- 

 ties which are particularly susceptible to scab. Therefore, 

 especially since no scab has ever been observed on the limbs of 

 the Ben Davis at Highmoor it was not surprising that the dif- 

 ference in the amount of scab obtained in sorting the fruits on 

 plots 1 and 8 was only about one-tenth of one per cent, or 

 plainly within the limits of experimental error. 



As has already been stated the use of the strong lime- 

 sulphur on plot 8, after the buds had enlarged sufficiently so 

 that the young leaves were beginning to show, caused very ap- 

 parent injury at the time, but no permanent ill effects were ob- 

 served on the foliage or in the reduction of the amount of fruit 

 set. On the other hand reference to Table 1 shows that only 

 about 78 per cent of merchantable fruit was obtained on plot 8 

 as compared with over 89 per cent on plot 1 which was sprayed 

 exactly the same, except it received no dormant spray applica- 

 tion, this difference being entirely due to the increase in russet- 

 ing on the former. 



Plot 8 consisted of trees 7 to 12, rows 11 to 14. The record 

 given in Table 1 is for the fruit harvested on the two central 



