DISSEMINATION OF THE STEM AND BULB INFESTING 
NEMATODE, TYLENCHUS DIPSACI, IN THE SEEDS OF 
CERTAIN COMPOSITES 1 
. By G. H. Godfrey, 
Pathologistj Office of Cotton, Truck, and Forage Crop Disease Investigations, Bureau 
of Plant Industry, United States Department of Agriculture 
The investigations recounted in this paper were carried on as. a result of the 
finding of the widespread occurrence of the stem-nematode-infested false dande¬ 
lion, Hypochaeris radicata , in the Pacific Coast States, as reported by Godfrey 
and McKay (2). 2 My subsequent discovery of the same nematode in the true 
dandelion, Taraxacum officinale, over a wide area in northeastern United States 
in July and September, 1923, made the problem of the manner of dissemination 
the more interesting. 
REVIEW OF LITERATURE 
A study of the literature has shown that both of these hosts are more or less 
abundantly infested by nematodes in Europe, 3 as indicated by their frequent 
mention by writers on plant galls. In 1885 Trail (19, p. 211) listed Hypochaeris 
radicata as subject to a gall caused by Tylenchus sp. He reported observing it 
first in Scotland, in 1882. This seems to be the earliest authentic report. In 
1886 Liebel (6, p. 547, No. 124) listed it as subject to a “ Hehninthocecidium ’ ’ 
which he described thus: 
Blattparenchym gallen: griinlichgelbe langliche Auftreibung der Blattmittelrippe, seltener riindliche 
bis langliche Auftreibung der Spreite. Die Aelchen darin in Anfcahl. 
Houard (3, p. 1035, No. 6040) in a comprehensive list of plant galls of Europe 
in 1909, listed this plant as having galls produced by “ Anguillulide,” Massa- 
longo (9, p. 8, No. 7) in 1915 listed it as subject to a “Hehninthocecidium” in 
Italy, described the symptoms, and illustrated with drawings typical affected 
leaves and stems, identical in appearance with the disease produced in this 
country by Tylenchus dipsaci (Kiihn) Bast. Thus this plant is reported all the 
way from Scotland to Italy as subject to galls produced by nematodes, it seems 
safe to assume by T. dipsaci. 
The true dandelion, Taraxacum officinale, was mentioned by Thomas in 1885 
(15) as subject to a “Hehninthocecidium,” and more completely described the 
next year (16, p. 304, No. 49). The causal organism was referred to as Tylenchus 
sp. in a still later paper (17). It was found, in this instance, in “Grosster Menge 
auf den Wiesen um Cogne, Gimilian und Lillian, Piemont, bei 1,500 to 1,800 m. 
Meereshohe.” Liebel (6, p. 573, No. 288), in 1886, reported a “ Hehninthoce¬ 
cidium” on this host at Bolchen, Lorraine. Riibsaamen reported it in 1890 
(13, p. 53, No. 207) in “Die Gallmiicken und Galle des Siegerlandes.” Houard 
(3, p. 1043, No. 6037) lists it for northern, central, and southern Europe as a 
Tylenchus gall. With Taraxacum again, though the specific parasite is not 
named, Tylenchus dipsaci is strongly indicated in every case. 
1 Received for publication Mar. 20, 1924. 
* Reference is made by number (italic) to “Literature cited," p. 478. 
3 1 gratefully acknowledge my indebtedness to Dr. G. Steiner, Office of Crop Technology, Bureau of 
Plant Industry, for his help in finding the pertinent European literature. 
Journal of Agricultural Research, 
Washington, D. C. 
(473) 
Vol. XXVIII, No. 5 
May 3,1924 
Key No. G-395 
