Oregon (Fischer 1944. Hardison 1945. Alderman 

 1988): and Wales (Neill and Hyde 1939). 



Worldwide. 56 host species have been reported as 

 susceptible to G. temulenta (table 1 ). Most hosts are in 

 the subfamily Pooideae. tribes Avenae and Poeae. 

 with heaviest infections reported in the genera 

 Agrostis, Festuca, Lolium, and Poa (Hardison 1962) 

 (table 2). Lolium perenne is widely recognized as 

 susceptible and has been identified as a host from all 

 countries reporting blind seed disease. In the Triticeae. 

 moderate to heavy infections were observed on 

 Psathyrostachys, Pseudoroegneria, and Secale 

 species. Grasses in the Bromeae appear less suscep- 

 tible, with little to no infection observed among 

 species of Broimts. 



In the United States, blind seed disease was found on 

 species of Agrostis, Aira, Alopecurus, Bromus, 

 Cynosurus, Deschampsia, Danthonia. Festuca, 

 Glyeeria, Hordeum, Holcus, Lolium, Phleum, and Poa 

 (table 1). Despite the susceptibility of many common 

 grasses in the United States. G. temulenta has been 

 reported only from Oregon. In New Zealand, blind 

 seed was reported on Agrostis, Cynosurus, Festuca, 

 Holcus, Lolium, Poa, and Secale cereale. In Northern 

 Ireland, blind seed was found on Agrostis, Cynosurus, 

 Festuca, Holcus, Lolium, and Poa. Additional host 

 reports include Calamagrostis from Germany, 

 Elytrigia from Norway, and Secale from France and 

 Germany. 



Most of these U.S. hosts were reported in a compre- 

 hensive host range study by Hardison (1962) (tables 1 

 and 2). However, there is one discrepancy in the U.S. 

 host range. Fischer (1944) reported G. temulenta on 

 Danthonia californica Boland (subfamily 

 Arundinoideae, tribe Danthoneae). Hardison ( 1962), 

 however, did not observe infection on D. californica 

 inoculated with G. temulenta under natural or artificial 

 conditions. Additional studies are needed to determine 

 all grasses that are susceptible to G. temulenta and 

 their relative susceptibility. 



Yield Loss and Economic Impact 



In the production of grass seed, loss from blind seed 

 disease occurs through a reduction in germinable seed 

 since infected seeds are ungerminable. In addition, 

 seed lots with germination below certification limits, 

 or below seed contract standards, are of less value and 



in some countries are unmarketable. Presence of G. 

 temulenta in import seed shipments may result in 

 rejection of the seed by some countries (Halfon- 

 Meiri 1978). 



Australia. Blind seed was reported to cause few crop 

 failures, although in 1969, 2,400 out of 9,000 acres 

 could not be certified because of blind seed disease 

 (McGee 1971a). 



Denmark. A low level of blind seed was found in 6 

 percent of ryegrass samples exported from Denmark 

 to Ireland (Lafferty 1948). A low level of blind seed 

 was also found in 1957 (Kristensen and Jorgensen 

 1960). 



England. In 1938 and 1939. germination as low as 50 

 percent was common in ryegrass (Noble and Gray 

 1945). In 1940. an average of 26 percent of ryegrass 

 seed from south England was infected (Gemmell 

 1940). 



The Netherlands. In 1965. the level of infection with 

 the blind seed fungus ranged from to 94 percent, 

 with an average infection rate of 19.2 percent (de 

 Tempe 1966). 



Scotland. In 1938-1939. infection of ryegrass seed as 

 great as 50 percent was reported (Gemmell 1940, 

 Noble and Gray 1945). Average infection in samples 

 from Ayrshire was 26.4 percent (Gemmell 1940). 



New Zealand. Between 1931 and 1934. cost of seed 

 lost to blind seed was estimated at £1,975^4,382 

 (Gorman 1939). In 1938, average germination of 

 ryegrass was 67-76 percent in Christchurch. Canter- 

 bury, and South Canterbury (Hyde 1938b). Greenall 

 (1943) reported germination of ryegrass as low as 1 

 percent. Greenall also noted that the severity of blind 

 seed disease depended on environmental conditions, 

 and he expected that in South Otago one year in every 

 two or three would be accompanied by poor germina- 

 tion. During 1944-1946, 45-84 percent of samples 

 from the South Island had more than 20 percent blind 

 seed and 10-22 percent of samples had 70-100 

 percent diseased seed (Blair 1947). Stocks of seed 

 throughout New Zealand had germination below 40 

 percent — in some lots as low as 5 percent (Osborn 

 1947). In seed exported from New Zealand to Ireland, 

 26 percent of samples had a low level of blind seed 

 disease (Lafferty 1948). 



