HOST SUITABILITY OF SELECTED WEED SPECIES TO FIVE <I>MELOIDOGYNE</I> SPECIES

Abstract

Kaur, R, J. A. Brito, and J. R. Rich. 2007. Host suitability of selected weed species to five Meloidogyne species. Nematropica 37:107-120. Weeds enable plant-parasitic nematodes to survive in the presence or absence of a crop, providing a source of nematode inoculum for the following season. Host suitability studies of 22 weed species commonly found in Florida, USA to five root-knot nematode species (Meloidogyne arenaria race 1, M. floridensis, M. incognita race 4, M. javanica race 1, and M. mayaguensis) were conducted under greenhouse conditions. Root-galling, egg mass indices and eggs per g of root were recorded at plant harvest. Reproduction factor (Rf = final population/initial population) was calculated to determine the host status for each plant species. Nine weed species (Abutilon theophrasti, Amaranthus retroflexus, A. spinosus, Cnidoscolus stimulosus, Cucumis anguria, Dichondra repens, Ipomoea triloba, Leonotis nepetaefolia, and Phytolacca americana) were good hosts (Rf ≥ 1) to the five root-knot nematode species evaluated, with average gall indices ranging from 4.2-8.0, and egg mass indices ranging from 2.8-5.0. Of these good hosts, Abutilon theophrasti sustained the highest number of nematode eggs (M. javanica) per g of root (102,560). The non-hosts of the five Meloidogyne spp. were Cassia occidentalis, Crotalaria spectabilis, Dactyloctenium aegyptium, Desmodium purpureum, Digitaria sanguinalis, Panicum dichotomiflorum, Oenothera biennis, Setaria pumila, and Sorghum halepense. Echinochloa muricata was a poor host (0.1 < Rf < 1.0) for M. arenaria and M. incognita, and non-host (Rf ≤ 0.1) for M. floridensis, M. javanica, and M. mayaguensis. Senna obtusifolia was a good host for M. mayaguensis (Rf = 37), but a poor host for M. floridensis (Rf = 0.3), M. incognita (Rf = 0.4) and M. javanica (Rf = 0.7), and a non-host for M. arenaria (Rf = 0). Current studies indicate that 12 out of 22 weed species tested are good hosts of at least one of the five nematode species evaluated.