New York Agricultural Experiment Station 141 



uiisprayed rows received an application of paris green in lime water 

 at about the same time. 



Although a little late blight (PhytophtJwra) was found on the un- 

 sprayed rows on August 27 it was not until September 9 that it 

 began to affect seriously the growth of the plants. By that time 

 it had become thoroughly established throughout the whole length 

 of the unsprayed rows, but was much worse in some places than in 

 others. About one-third the distance across the field from the south 

 end the unsprayed rows ran across a strip of soil which was some- 

 what dift'erent from the rest of the field, being moister, darker in 

 color and less sandy. It was here that the vines grew largest and 

 the blight was most destructive. After crossing this strip of black 

 soil the rows ran up a hillside where the soil was light in color and 

 quite sandy. In this region blight never made rapid progress al- 

 though it worked steadily among the plants and did them much 

 damage. However, the contrast between the sprayed and unsprayed 

 rows became very marked here. The unsprayed rows took on a 

 sickly, yellowish color. This condition was quite noticeable Septem- 

 ber 9 and continued to be prominent throughout the season, being 

 most conspicuous about September 15. A great many leaves were 

 quite yellow. No doubt this yellowing was partly the result of 

 blight, but it could not have been wholly due to that cause. Many 

 of the yellow leaves showed no blemish whatever. Moreover, where 

 the unsprayed rows ran across the black, moist soil there was scarcely 

 any yellow foliage although it was here that blight was most virulent. 



But, whatever the cause, spraying corrected the trouble. On Sep- 

 tember 15 when the unsprayed rows were decidedly yellow the 

 sprayed rows adjacent were dark green with scarcely a yellow leaf 

 to be seen. The contrast was very striking. We have frequently 

 observed that the foliage of sprayed plants is darker green than that 

 of unsprayed plants, but have never before seen the difference so 

 marked. We consider this an exceptionally good example of the 

 stimulating effect which bordeaux mixture is believed to have on 



