RUST AND MILDBW IN INt)IA. 45 



Provinces the weather conditions and the outturns of 1877, 1878, 

 and 1883, but especially 1878, strongly support the view I hold, 

 that the deficient outturns were very probably due to the parasite. 

 In the Punjab the case appears to me to be even stronger, as the years 

 1877, 1878, 1879, 1880 and 1881 were all years in which the 

 weather conditions favoured the development of the fungus, and in 

 which the outturns were lower than we should otherwise have ex- 

 pected them to be ; while, on the other hand, the years 1882, 1883 

 and 1884 were adverse to fungal development, and the outturns 

 steadily rose. Lastly, in the North-West Provinces and Oudh the 

 conditions do not stand in strong relief, either for or against my 

 argument. The weather conditions of 1877 and 1878 were on the 

 whole favourable to both host and parasite, and the outturns fell, 

 pointing to the fungus as the cause. In the years 1876 and 1880 

 the conditions were fairly favourable to the host, but decidedly 

 unfavourable to the fungus, and in each year a rise in outturn was 

 recorded. In 1881 and 1883, conditions were on the whole favour- 

 able to the host, and favourable to the fungus in March ; but the 

 favourable weather for the latter came late, and the outturn in the 

 former year was slightly increased, and in the latter year remained 

 stationary. 



I will now proceed to make a few remarks regarding the causa- 

 tion of the disease. Long before De Bary rediscovered," in 1865, 

 by actual experiment, the connection between the barberry iEcidium 

 and the rust of corn, such a connection was firmly believed in by 

 farmers, both in Europe and America ; and, indeed, the compulsory 

 removal of all barberry bushes was enforced by legislation in 

 several places, e. //., by the Barberry Law of Massachusetts, pub- 

 lished on Jan. 18th, 1755. This fungus, whose life-history is 

 completed on the barberry, and cereals (wheat, barley, rye, oats), 

 and certain wild grasses, goes by the name Pitccinia graminis Pers. 



disnostic 



ly stag 



known as "rust") is more oval than round, and has two germ- 

 spores on the short equator opposite one another; and that the 

 teleutospores (i. e., the spores from the black pustules, which are 

 formed later, and which constitute the disease popularly known as 

 "mildew") are naked, i.e., not covered by the epidermis of the 

 host, are much thickened at the apex, which is also well rounded, 

 and are provided with long stalks. This fungus is the most 

 prevalent, and probably the most destructive, in Europe. There 

 are, however, two other species of rust and mildew whose life- 

 cycles in Europe were likewise discovered by De Bary on the same 

 crops. These are (2), Pitccinia ntbi/fo-vera DC. (synonyms, P. 

 striaformis Westendorp, and P. straimnis Fuckel) ; and (3), Puccinia 

 coronata Corda. The former completes its life-history on several 

 species of borages, and the latter on some species of buckthorn 



* A Danish schoolmaster, Schoeler, appears to have been the first to demon- 

 strate, by actual experiment, the genetic relationship between the barberry 

 JEcidium and the rust and mildew of cereals. (See A Monograph oj the British 



Uredinea, by C. B. Plowright, 1889, pp. o'2—5±). 



