204 Report of the Botanical Department of the 



RESULTS. 



effect of the sprays on the foliage. 



In addition to the desirability of testing the value of lime-snl- 

 phur as compared with bordeaux as a preventive of potato blight 

 {Fhytophthora infestans) it was one of the objects of this experi- 

 ment to determine the effect of the two preparations on the 

 foliage. At short intervals during the season notes were taken 

 upon the condition of the foliage in the experimental field. The 

 weather following planting was such as to induce a satisfactory 

 growth, and at the end of the sixth week the plants were about 

 eight inches high, in full foliage, even all over the field, and 

 growing vigorously. At this time, July 9, the first application 

 of the spray mixtures was given. Previous to the third spraying 

 all the rows looked very uniform in size and color of foliage, 

 but on August 6, following the third spraying, more yellow and 

 dead leaves were noticed on the lower branches of the plants in 

 the lime-sulphur rows and the check rows, than on the bordeaux 

 rows, which, with the exception of an occasional dead leaf, were 

 entirely free and presented a vigorous appearance. Flea-beetle 

 injury, while very slight, was more prevalent on the lime-sulphur 

 and check rows than on the bordeaux rows, no doubt due to the 

 deterrent properties of the bordeaux. About August 16 tip- 

 burn appeared and continued to increase gradually in ex- 

 tent upon the lime-sulphur rows and the checks until the 

 end of the season. The bordeaux rows were nearly free from 

 it during the entire season while on the lime-sulphur rows it 

 appeared as if the trouble was aggravated by the lime-sulphur 

 spray. A large percentage of the plants in the lime-sulphur rows 

 were completely dead from the effects of the tipbum several days 

 before many plants had died in the check rows. It cannot be 

 stated that this trouble called tipbum was due to insufficient mois- 

 ture owing to the fact that it appeared more destructive during 

 the latter part of the season and at a time when rains were 

 frequent, often preventing cultivation for several days. It also 

 appeared more destructive on the north half of the field which" 

 was slightly lower than the south half of the field. 



