Abstract
Five trichodorid species associated with the roots of woody plants are described and illustrated. Trichodorus tricaulatus n. sp. is characterized by its shape of posterior part of oesophageal bulb, which extends slightly over the intestine, three ventromedian cervical pores of the male, and the anterior half of spicules being striated. T. aequalis Allen, 1957, previously known only from North America, is described from central Japan. T. longistylus Yokoo, 1964, and T. kurumeensis Yokoo, 1966, are designated as junior synonyms of T. cedarus Yokoo, 1964, to which additional description is given. This species has a wide host range and probably is the most widespread trichodorid species in Japan. Paratrichodorus (Atlantadorus) porosus (Allen, 1957) was also found to parasitize a wide variety of woody plants. Variation in the number of ventromedian advulvar pores was found in several populations of this species. P.(Nznidorus) minor (Colbran, 1956) is less abundant in the study site but is considered native to Japan.
Attention is drawn to the intraspecific variation in three Trichodorus species.
