Weed Hosts of Root-Knot Nematodes in Tomato Fields

Weed Hosts of Root-Knot Nematodes in Tomato Fields Root-knot nematodes (Meloidogyne spp.) are one of the three most economically damaging genera of plant parasitic nematodes on horticultural and field crops. Root-knot nematodes are distributed worldwide, and are obligate parasites of the roots of thousands of plant species. All major field crops, vegetable crops, turf, ornamentals, legumes and weeds are susceptible to one or more of the root-knot species. In this study, nineteen weed species were found to be hosts for Meloidogyne incognita, M. javanica, M. arenaria race 2, and M. hapla in tomato fields in Khorasan Province, Iran. Egg mass production and galling differed (p < 0.05) among these weed species: Amaranthus blitoides, Portulaca oleracea, Polygonum aviculare, Convolvulus arvensis, Cyperus rotundus, Plantago lanceolatum, Rumex acetosa, Solanum nigrum, Datura stramonium, Acroptilon repens, Alcea rosa, Alhaji camelorum, Chenopodium album, Echinochla crusgalli, Hibiscus trionum, Kochia scoparia, Malva rotundifolia, Setaria viridis, Lactuca serriola. The species P. oleracea, A. blioides, S. nigrum, P. lanceolatum, Ch. album, and C. arvensis are major threats to the natural ecosystem in the Iranian province of Khorasan. A. blitoides collected from tomato fields was a good host for 4 Meloidogyne species. C. arvensis, as an important weed, was a distinguished appropriate host for M. hapla, M. incognita, M. javanica. S. nigrum and Ch. album were good hosts for M. hapla, M. javanica, M. incognita race 1, and M. arenaria race 3. In this survey, we reported E. crusgalli as a new host of M. javanica and C. rotundus was a good host for M. arenaria and M. incognita. S. nigrum was also reported as a new host of M. hapla. R. acetosella was reported as a host of M. arenaria. M. incognita was recently described as a new species infecting D. stramonium worldwide.