A Study of Meadow-Crop Diseases in New York 87 



inhibiting germination. Koloclust probably would give protection against 

 the disease in the field. 



TIMOTHY RUST 



Suscepts 



The results of a great number of cross inoculations between timothy, 

 cereals, and wild grasses reported in the papers of Eriksson (1894), Kern 

 (1909), Arthur (1909), Johnson (1911), Pammel and King (1912), Mercer 

 (1914), Stakman and Jensen (1915), Stakman and Piemeisel (1916 and 

 1917) have been compiled. The plants shown to be infected more or less 

 readily from inoculations with urediniospores from timothy are: Avena ela- 

 tior, Avena fatua, Avena saliva, Bromus tectorum, Dactylis glomerata, Elymus 

 virginicus, Festuca elatior, Hordeum jubatum, Hordeum vulgare, Lolium itali- 

 cwn, Lolium perenne, Poa compressa, and Secale cereale. The following plants 

 have been inoculated by investigators from time to time without positive 

 results: Agrostis alba, Agropyron occidentale, Elymus canadensis, Elymus 

 robuslus, Holcus lanalus, Hystryx hystrix, Phalaris arundinacea, Poa 

 pratensis, Triticum vulgare, and Mahonia aquifolium. As a result of their 

 studies, Stakman and Piemeisel conclude that the following plants may be 

 infected in nature with timothy rust: Dactylis glomerata, Festuca elatior, 

 Fetuca pratensis, Koeleria cristala, and Phleum pratense. 



Whether the barberry, Berberis vulgaris, is susceptible to the rust is 

 still debatable. Eriksson (1894) did obtain infection once under uncon- 

 trolled conditions, but apparently no one has been able to confirm the 

 experiment. As far back as 1864 Settegast observed that timothy can 

 grow very near rusted barberries without becoming diseased (1864:384). 

 It should be pointed out here that timothy is susceptible not only to tim- 

 othy rust but also to Puccinia coronata, oats-form and lolium-form (Melhus, 

 Dietz, and Willey, 1922 : 225 and 227) ; and to Puccinia graminis avenae 

 (Stakman and Piemeisel, 1916:816) but is not susceptible to Puccinia 

 graminis agrostis (Stakman and Piemeisel, 1917:470), to Puccinia graminis 

 tritici (Carleton 1899:54, Stakman and Piemeisel, 1917:470), nor to 

 Puccinia graminis hordei (Stakman and Jensen, 1915:213). 



The general consensus of opinion among investigators seems to be that 

 no timothy varieties are immune to timothy rust, although much resistance 

 is indicated by some of them. Clark (1910:431) observed that "some 

 plants show great susceptibility to the attacks of this fungus, being com- 

 pletely covered with the pustules. On the other hand, a few plants have 

 been observed which are very nearly immune." 



As a result of their study of varietal susceptibility, Hayes and Stakman 

 (1919:68) say that " the striking fact is that the Cornell selections show a 

 high percentage of resistant plants, while the Minnesota selections are 

 very susceptible." 



