NEMATODE DISEASE OE WHEAT. 29 
wheat, although apparently not to so great a degree. Further care- 
ful observations in the field and more adequate cross-inoculation 
experiments are necessary, however, in order definitely to deter- 
mine the relation of the nematode to these cereals. 
On many wild grasses, flower galls due to species of nematodes 
closely related to and by many believed to be identical with Tylen- 
chus tritici have been found by both European and American ob- 
servers. Bessey (4) in 1905, for example, reported that he had 
found such galls in grasses of the genera Chaetochloa, Agropyron, 
Elymus, Calamagrostis, and Trisetum collected in Texas, Oregon, 
and Alaska, but was unable to determine whether any of them were 
induced by an eel worm identical with the wheat nematode. Some in- 
vestigators have given the causal organism occurring on the various 
grasses specific names, such as Tylenchus agrostidis, T. graminearuni, 
and T. phalaridis, depending largely upon the host attacked, and 
sometimes in the brief inadequate description of these parasites the 
writers have pointed out minor differences between them and Tylen- 
chus tritici. On morphological grounds alone these described dif- 
ferences are not sufficient to warrant separating them from the wheat 
nematode, and for this reason Dujardin (13), Diesing (12), and 
Bastian (2) in their helminthological monographs have considered 
them identical with Tylenchus tritici. Whether the gall-producing 
nematodes discovered on different grasses are physiologically alike 
in parasitism can, of course, be determined only by cross-inocula- 
tion experiments, a thing which the above-mentioned investigators 
apparently did not attempt. Marcinowski (22), however, in an ex- 
periment covering two years, failed to induce flower infection of 
many grasses with Tylenchus tritici. Each plant during the first 
year was inoculated with the larvae of several hundred wheat galls 
and during the next year was again treated with the larval content of 
about 300 galls. The grasses used in the experiment were, for the 
most part, those on which galls had been reported. They are as 
follows : 
Agrostis capillaris, A. stolonifera, A. canina. 
Bromus erectus, B. pratensis, B. secalinus. 
Alopecurus geniculatus. 
Festuca ovina, F. pratensis, F. vulgaris. 
Holcus Imiatus. 
Poa annua, P. pratensis. 
Phleum oohmeri, P. pratense. 
Although suspicious symptoms appeared in the leaves during the 
second year on Festuca vulgaris, Poa annua, and Alopecurus genic- 
ulatus, not a single gall was found on any of these hosts, and the 
fruit matured normally. 
