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The ornamental Tagetes minuta is a herbaceous plant of the Asteraceae family. T. minuta, a species native to southern South America, is used as a condiment, as a refreshing beverage, and for medicinal purposes. In 2011, disease symptoms of yellowing, root and foot rot, drying of leaves, and plant death were observed in an ornamental marigold (T. minuta) greenhouse in Fars province. The infected plants were collected and transferred to a laboratory. Samples were washed, cut into small pieces, surface disinfested with a 0.5% NaClO solution, and cultured on Potato Dextrose Agar (PDA) acidified to pH 4.5 with 0.5% lactic acid. Based on morphological characters, the causal agent was identified as Cylindrocarpon destructans. To confirm morphological identification, DNA was extracted from isolates using a genomic DNA purification Kit. The region of internal transcribed spacers 1, 2, and 5.8S genes of rDNA were amplified using the ITS4 and ITS1 universal primer set. Fragments of 600 bp were recovered from PCR, purified, sequenced, edited, and deposited in GenBank. The isolates had a 100% identity with all the compared C. destructans sequences. The pathogenicity tests were done with a suspension of 1 × 106 conidia per ml homogenised in sterile water. The symptoms on inoculated plants were similar to those previously observed and the fungus was reisolated from the inoculated plants. This is the first documented report of C. de-structans as a cause of root and foot rot disease on T. minuta in Iran.
The distribution of nematodes was studied in rice fields in Guilan province, Iran, from 2014 to 2016. Nematode biodiversity of 250 soil and root samples was examined. Thirty nematode species were identified morphologically, including plant parasites, microbivores and mycetophagous and predator species. Molecular techniques were also used for further identification of three plant parasitic species. Indicators of population were also estimated. Spiral nematodes (Helicotylenchus crenacauda Sher, 1966 and H. digitiformis Ivanova, 1967) and stunt nematode (Tylenchorhynchus agri) were the predominant parasitic species identified. Among other species, three mononchid species were identified namely Mononchus aquaticus, Mylonchulus sigmaturus and M. polonicus. The species M. polonicus was found and reported in Iran for the first time. The two plant parasitic species T. agri and Xiphinema index were reported in association with rice in Iran for the first time. To evaluate the distribution and incidence of Aphelenchoides besseyi (rice white-tip nematode) in different regions of Guilan province, a total of 255 fresh seed samples were collected/inspected, of which, about 40% of them were infested with A. besseyi. Of the 16 studied counties, the highest percentage of infected seeds came from fields around the city of Astara (69.2%) and the second highest infection was observed near the city of Anzali (60%).
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Weed hosts of root - knot nematodes in tomato fields

71%
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.
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