The Take-all Disease of Cereals and Grasses 11 



were reported as immune in the first tests, were found during the second 

 tests to be susceptible to the take-all pathogene. All grasses found to 

 be hosts in the first series of tests became affected again in the second. 

 The grasses reported as hosts under field conditions were, in every case, 

 found in wheat fields infested with take-all. Infected Agropyron repens 

 was observed in nearly all of the 137 take-all-infested wheat fields visited 

 in 1922 and 1923 and this seems to be the most susceptible wild grass 

 in New York. Poa compressa was found infected in Tompkins County 

 only, where it was almost as heavily infected as Agropyron repens. Bromus 

 secalinus, Agrostis palustris, and Phleum pratense were found to be infected 

 in Cayuga, Wayne, and Tompkins Counties, but never more than one 

 or two perithecia could be found on a plant. Under field conditions in 

 New York State, however, the grasses appear to be tolerant to the take- 

 all organism, since they are rarely severely stunted even when heavily 

 infected. 



Cereals 



Apparently take-all is restricted to the small grains. Concerning their 

 relative susceptibility, Hori (1901), reporting on the situation in Japan, 

 states that barley and rye are slightly more susceptible than wheat since 

 they exhibit a greater degree of stunting and have their yields reduced 

 more than does wheat. Oats are reported in Australia (Anonymous, 1919) 

 as being less affected than wheat and barley, but not immune, while 

 Richardson (1911) reports that oats are not affected by take-all. Rice 

 has been reported by Hori (1901) and Tanaka (1917) as being very 

 slightly susceptible to take-all. 



The present investigations indicate that spring-planted barley and oats 

 growing under field conditions either escape or are immune to take-all, 

 and that spring-planted wheat becomes infected only under conditions 

 which are extremely favorable to the pathogene. Rye is apparently very 

 much more resistant than wheat. When winter lye and ten varieties of 

 winter wheat were grown in a field test in 1922 to determine their relative 

 susceptibility, 87 per cent of the rye plants and 96.6 per cent of the wheat 

 plants were diseased. Among these diseased plants there was no stunting 

 of the rye plants, but 75.6 per cent of the wheat plants were stimted. This 

 difference in resistance is further borne out by the fact that in badly 

 infested wheat fields volunteer rye is very seldom diseased. 



Under greenhouse conditions wheat was the most susceptible of the 

 cereals; barley was more resistant that wheat but less resistant than 

 rye, which was very slightly affected; oats and rice appeared to be immune. 



It seems that under New York conditions winter wheat is the only 

 cereal which will be seriously damaged by take-all. However, in warmer 

 sections of the United States where winter barley is grown, the disease 

 may cause a considerable loss to that crop. Rye will probably never 

 suffer any appreciable injury from the disease in New York. Spring- 



