Influence of Nonhost Plants on Population Decline of Rotylenchulus reniformis

  • E. P. Caswell
  • J. DeFrank
  • W. J. Apt
  • C. S. Tang


The influence of Chloris gayana, Crotalaria juncea, Digitaria decumbens, Tagetes patula, and a chitin-based soil amendment on Hawaiian populations of Rotylenchulus reniformis was examined. Chloris gayana was a nonhost for R. reniformis. The nematode did not penetrate the roots, and in greenhouse and field experiments, C. gayana reduced reniform nematode numbers at least as well as fallow. Tagetes patula was a poor host for reniform nematode and reduced reniform nematode numbers in soil better than did fallow. Crotalaria juncea was a poor host for R. reniformis, and only a small fraction of the nematode population penetrated the roots. Crotalariajuncea and D. decumbens reduced reniform nematode populations at least as well as fallow. A chitin-based soil amendment, applied at 2.24 t/ha to fallow soil, did not affect the population decline of reniform nematode. Key words: allelopathy, chitin, Chloris gayana, cover crop, Crotalaria juncea, Digitaria decumbens, Hawaii, marigold, nematode management, nematode population decline, pangola grass, reniform nematode, rhodes grass, soil amendment, sunn hemp, Tagetes patula.