Reproduction of Meloidogyne enterolobii on weeds found in Brazil

Abstract

Weeds host of root-knot nematodes (Meloidogyne spp.), parasites of important crop plants mainly in tropical and subtropical regions, enable them to maintain themselves or increase their abundance in soils. To evaluate the host status of 31 weed species that commonly compete with crops, we experimentally inoculated them with 5000 eggs and second-stage juveniles (J2) of Meloidogyne enterolobii. Sixty days after inoculation, we measured several parameters related to infestation ability, including gall index (GI), number of eggs/g root, and reproduction factor (RF). About 77.4% (n = 24) of the weed species we assessed were susceptible (RF ≥ 1) to M. enterolobii infestation: Acanthospermum australe, Amaranthus deflexus, Amaranthus hybridus, Amaranthus spinosus, Amaranthus viridis, Bidens pilosa, Bidens subalternans, Cardiospermum halicacabum, Commelina benghalensis, Euphorbia heterophylla, Galinsoga parviflora, Ipomoea grandifolia, Ipomoea nil, Ipomoea purpurea, Leonurus sibiricus, Nicandra physaloides, Polygonum hydropiperoides, Portulaca oleracea, Rhynchelytrum repens, Sida rhombifolia, Solanum americanum, Solanum sisymbriifolium, Solanum pseudocapsicum, and Talinum paniculatum. In contrast, seven species were resistant (RF < 1) to M. enterolobii infestation: Conyza bonariensis, Cyperys rotundus, Digitaria horizontalis, Digitaria insularis, Eleusine indica, Raphanus raphanistrum, and Senecio brasiliensis. Management strategies to control M. enterolobii should identify susceptible weeds in crop fields and control these potential alternative hosts of the parasitic nematode.