Susceptibility of Japanese holly to Criconemoides xenoplax, Tylenchorhynchus claytoni, and certain other plant-parasitic nematodes.

Three cultivars of Ilex crenata: 'Helleri', 'Convexa', and 'Rotundifolia' were inoculated with either Criconemoides xenoplax, Helicotylenchus dihystera, Hoplolaimus galeatus, Trichodorus cltristiei, or Tylenchorhynchus claytoni at 0, 200 (low), or 2,000 (high) nematodes/ 15-cm diam pot. Plants were kept in the greenhouse 10 mo prior to transplanting into 2.25 m(2) field plots. Helleri was severely stunted by C. xenoplax. Criconemoides xenoplax and T. claytoni caused lower plant vigor and top weights of Rotundifolia after 3 years. Above-ground symptoms included stunting, chlorosis, and leaf drop. Convexa was not susceptible to the nematodes tested. Low and high initial populations of the five nematodes tended to reach equilibria over the 3-year sampling period. Helicotylenchus dihystera and C. xenoplax occurred in the greatest densities regardless of host. None of the test plants were damaged by H. dihystera. Convexa was the least suitable host for nematode reproduction. Hoplolaimus galeatus, which was originally isolated from cotton, failed to reproduce or survive on any plant tested. Nematode densities over the 3-year sampling period did not always lit a linear regression model.