Four new hosts for Heterodera daverti


  • D. Nordmeyer
  • R. A. Sikora


A cyst nematode was found in pastures and seed multiplication plots of Trifolium subterraneum L. in Northwest Tunisia and identified initially as Heterodera trifolii Goifart, 1932 (Sikora, 1977). Wouts and Sturhan (1978) redescribed H. trifolii Goifart, 1932 from a neotype population and separated from it the closely related species H. daverti Wouts et Sturhan, 1978. The nematode from Tunisia identified originally as H. trifolii was reidentified as H. daverti (Nordmeyer, 1979; Wouts and Sturhan, 1978, pers. communications). The nematode on T. subterraneum caused yield reductions and was found in the field associated with several soil-borne fungi in a root-rot complex (Nordmeyer et al., 1978). Four Trifolium species which occur as wild types in Tunisian pastures of T. subterraneum and which had not been described as host plants for H. trifolii Goifart, 1932 were tested as hosts for H. daverti. Twenty seeds of T. angustifolium L., T. arvense L., T. campestre Schreber and T. striatum L. were sown in steam-pasteurized soil in 10 cm diam pots, replicated four times, and kept in an illuminated incubator at 25°C. Ten days after germination, each pot was inoculated with 2000 freshly hatched H. daverti juveniles and the number of cysts produced was recorded four weeks later. The nematode developed on all four Trifolium species. All cysts contained eggs. The number of cysts produced was 5/pot on T. angustifolium, 7 fpot on T. campestre and 1O/pot on T. arvense and T. striatum; this is a low multiplication in view of the inoculum density and the cysts were smaller than those that developed on T. subterraneum. In addition to these four hosts and T. subterraneum, H. daverti has been reported from T. repens (Wouts and Sturhan, 1978) and T. alexandrinum (Anon. 1979). Additional research is needed to determine which of the approximately 125 hosts of H. trifolii Goffart, 1932 are hosts for H. daverti and H. trifolii.