POTATO DISEASES IN I907. 299 



amount of early blight on Plot 3 as on Plot 2, but in both cases 

 it was much more destructive on the outer, unprotected leaves. 

 In fact on all the plots at Foxcroft after the middle of Septem- 

 ber a distinct black line could be observed midway between the 

 rows. This was made by the browning of the unprotected 

 leaves as a result of the combined injuries of early blight, flea 

 beetles and grasshoppers. The repellent qualities of bordeaux 

 upon the insects mentioned was very marked. 



At Houlton late blight could be found after August 20 on 

 all the plots where the leaves were imperfectly protected at the 

 margins, Plot 1 looking a little the healthiest, with not much 

 choice between the other two. These plants were killed by 

 fiost on September 8. There was practically no early blight 

 or: the Houlton field. The crop at both places was harvested 

 during the week beginning October 14. The yields and amount 

 of rot are given below in tabular form. 



Yields of Potatoes from Single and Double Spraying in 

 Bushels per Acre. 



Total yield Net yield Rot per Per cent 

 per acre. per acre. acre. of rot. 



Foxcroft. 











Plot i 5 Double Sprayed 











6 times, 



345 



343 



2 



0.6 



Plot 2, Double Sprayed 











3 times,* 



303 



298 



5 



1-7 



Plot 3, Single Sprayed 











6 times, 



300 



280 



20 



6.6 



Houlton. 











Plot 1, Double Sprayed 











6 times, 



462 



420 



42 



9.1 



Plot 2, Double Sprayed 











3 times, 



362 



277 



85 



23-5 



Plot 3, Single Sprayed 











6 times,* 



392 



343 



49 



12.5 



* See note on p. 298. 



