208 Keport of the Botanical Department. 



CONCLUSIONS. 



The infonnation at hand is quite sufficient as a basis for some 

 final conclusions. It seems evident that lime-sulphur is not 

 destined to take the place of bordeaux mixture as a spray lor 

 potatoes, in spite of the fact that it is cheaper and no doubt very 

 convenient to use. Under more favorable conditions, in which 

 late blight occurred earlier in the season and to a greater extent, 

 the treatment with lime-sulphur might have produced different 

 results, but at present it is not promising. However, the experi- 

 ments have not been carried far enough to determine what may 

 be expected under favorable conditions. 



The lime-sulphur proved harmless to the potato foliage as far as 

 burning is concerned, but it proved to have a distinct dwarfing 

 effect quite similar to that noted in the previous season's experi- 

 ment. The lime-sulphur also lacked the beneficial or stimulative 

 effect derived from the bordeaux mixture which preserved the 

 foliage and prolonged the life of the plants and thereby increased 

 the yield even in the partial absence of fungus diseases. 



It could not be determined at just what time in the season or 

 after which application the dwarfing effect of the lime-sulphur 

 first occurred, but it was first noticeable on August 20 at the 

 time of the fourth spraying, and on August 25 following this 

 spraying it became quite marked. It therefore appears that the 

 injury is cumulative. The benefical effect of the bordeaux on 

 the foliage was observed on August 6 or approximately two weeks 

 before the injurious effect of the lime-sulphur was noticed, when 

 it was plainly evident that there were many yellow and dead 

 leaves on the lower branches of plants in the lime-sulphur rows 

 and in the check rows while there were practically none on the 

 bordeaux rows which held their foliage throughout the seasorw 



In general, then, we are led to the same conclusions published in 

 last year's bulletin on a similar experiment, namely, that spraying 

 potatoes with bordeaux mixture increases the yield of tubers and 

 prolongs the life of the plants; while the use of lime-sulphur 

 dwarfs the plants, causes them to die earlier, and causes an appre- 

 ciable loss in yield. Certain it is that spraying potatoes with 

 bordeaux mixture should not be omitted by the potato grower. 



