Research Papers: Relationship between Nematode Density and Weed Density in Avocado Groves


  • R. McSorley
  • C. W. Campbell


Helicotylenchus dihystera, Persea americana, Pratylenchus brachyurus, Quinisulcius acutus, Rotylenchulus reniformis, Reniform Nematode, Lesion Nematode, Tropical Fruit Trees


The relationship between density of plant parasitic nematodes and weed density was examined in three Florida groves planted to avocado (Persea americana). Soil and root samples were collected from 24 trees in each of two groves and from 80 trees in a third grove and assayed for plant parasitic nematodes. A rating of the percent of ground area beneath each tree covered by individal weed species and by all weed species together was obtained and correlation coefficients between each nematode density and each corresponding weed density were computed. Numbers of Rotylenchulus reniformis per 100 cm of soil were correlated with total weed density at two of the three sites, with r = 0.233* (78 d.f.) and r = 0.602** (22 d.f.). Density of R. reniformis also showed a significant (P = 0.05) correlation with densities of several individual weed species at these two sites, including a weed host, Bidens pilosa. While R. reniformis density was not significantly correlated with total weed density at