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STUT3r3Y-RnOT NI-mTODES (TRICHODORUS SPi'.) 



"8fcubby-root" and "stubby-root nematode" have been £;u,f;f;eGtcd as coTnmon 

 names for the disease and the causal organism, respectively, by Christie 

 and Perry (1951). Since this report of Trichodorus being the causative 

 agent of diseases of various crop plants in Florida, considerable atten- 

 tion has been given to the genus. Now that a monograph of the genus has 

 been prepared by Allen (1957) progress can be expected in the study of 

 this interesting plant-parasitic genus. The Taxonomic key from the 

 monograph is included for use in these Notes. 



These nematodes are not in the Class Phasmidia as have been the previ- 

 ously mentioned generaj rather, they are in the Class Aphasmida, Dory- 

 laimoidea. The species are small (0.5 to 1.5 mm. long), thick-bodied, 

 cylindrical nematodes, tapering at the anterior end. Fixed specimens 

 often appear as though they had a swollen condition of the cuticle or 

 as though they had retained the last molted cuticle. Allen (1957), who 

 made studies of cross sections of these nematodes, points out that the 

 spear or stylet should be referred to as a dorsally located tooth. This 

 onchiostyle is hollow but not throughout its entire lengthy axid, although 

 it may be used for puncturing cells, the actual feeding is by a somewhat 

 different mechanism than in nematodes having a hollow axial stylet. 



These nematodes have been found associated with the roots of a diversity 

 of plants and from many different localities. Perhaps, primarily exter- 

 nal feeders, thorough examination of the soil rather than of the roots 

 may be necessary for finding these nematodes. Allen (1957) suggests 

 that it may be preferable to confine the use of the name "stubby-root 

 nematode" to Trichodorus christiei, since no other species of the genus 

 is known to produce the type of symptoms that are associated with the 

 feeding of this species. T. christiei appears at the present to be the 

 most tcidely distributed species of this genus in the United States and 

 is reported from the root zones of quite a number of economic and orna- 

 mental plants. Old host listings or reports of T. primitivus prior to 

 1957 should be used with caution because, until that time, only this one 

 species had been described. 



Literature Cited 



Allen, M. W. 1957- A review of the nematode genus Trichodorus with 

 descriptions of ten new species. Nematologica 2(1) :32-52. 



Christie, J. R. and V. G. Perry. 1951. A root disease of plants 



caused by a nematode of the genus Trichodorus . Science 113:1491- 

 U93. 



