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The root-lesion nematode of the genus Pratylenchus Filipjev (1936) has a worldwide distribution and cause severe production constraints on numerous important crops. In 2013-14, during a survey of the apple nurseries and orchards in center of Tunisia (Kairouan, Zaghouan, Monastir and Kasserine), 70 different roots and soil samples were collected. The populations of root-lesion nematode were identified on the basis of their morphological and morphometric characters, and by molecular methods. Microscopic observation of females and males demonstrated the occurrence of Pratylenchusd vulnus on apple trees. The ribosomal DNA D2-D3 expansion segments of the 28S rRNA and of the Pratylenchus populations were PCR amplified and sequenced. The sequences were compared with those of Pratylenchus species in the GenBank database with high similarity (99%). This comparison reconfirmed the morphological identifications. Phylogenetic studies placed those populations with P. vulnus. This is the first report of P. vulnus infecting apple in Tunisia. [ABSTRACT FROM AUTHOR]

The present study was carried out to assess the nematicidal potential ofPunica granatumL. against the root-knot nematodeMeloidogyne javanicaresponsible for yield losses in tomato. Varied concentrations of methanolic, ethanolic and aqueous extracts from pomegranate peels were investigated for activity against eggs and juveniles ofM. javanicainin vitroassays. All extracts used significantly inhibited egg hatch by over than 75%, but viability of second-stage juveniles (J2) was not significantly inhibited by ethanolic extract. Aqueous extract was assessed at the concentration of 10, 25 and 50% againstM. javanicaon tomato in greenhouse trials; pomegranate peels powder was also tested at the rate of 3, 6 and 9 g as a soil amendment. Both extracts significantly reduced nematode infestations; aqueous extract enhanced plant growth but powder amendment exhibited a phytotoxicity compared to the untreated plants. The reduction in number of galls, egg masses and nematode reproduction rate was recorded. [ABSTRACT FROM AUTHOR]

Overusage of chemical fertilizers by farmers had adversely impacted soil fertility and agricultural ecosystem sustainability. To explore safer alternatives, six bio-treatments based on two Bacillus spp. consortium and three biological inputs were investigated. Assessments, carried out over two consecutive cropping years, were focused on their effects on soil microbial traits, pepper production and health status as measured by fungal and nematode infection levels. Rhizosphere microbial populations were more abundant at the second cropping year than at the first one, thus indicating their cumulative effects. The two Bacillus spp. strains applied individually, and Acadian input had induced significant increments in pepper production by 22–25% over control. No significant differences were recorded between two Bacillus spp. and their consortium on the severity of pepper-associated soil-borne diseases. B. amyloliquefaciens subsp. plantarum SV65 performed 39.7 and 59.6% better than Acadian and Trianum-P® in reducing nematode galling index and foliar severity index, respectively. Interestingly, single treatment using B. amyloliquefaciens subsp. plantarum SV65 performed better than the three biological inputs based on the majority of tested parameters. Thus, this strain used individually or in combination with B. subtilis SV41 is a promising eco-friendly alternative for the enhancement of pepper health and production. [ABSTRACT FROM AUTHOR]

Spiral nematode species of the genus Rotylenchus have been reported on olive (Olea europaea L.) in several Mediterranean countries (Castillo et al., 2010; Ali et al., 2014). Nematological surveys for plant-parasitic nematodes on olive trees were carried out in Tunisia between 2013 and 2014, and two nematode species of Rotylenchus were collected from the rhizosphere of olive cv. Chemlali in several localities of Tunisia (Tables 1,2). Twenty-two soil samples of 3 to 4 kg were collected with a shovel from the upper 50 cm of soil from arbitrarily chosen olive trees. Nematodes were extracted from 500 cm³ of soil by centrifugal flotation method (Coolen, 1979). Specimens were heat killed by adding hot 4% formaldehyde solution and processed to pure glycerin using the De Grisse's (1969) method. Measurements were done using a drawing tube attached to a Zeiss III compound-microscope. Nematode DNA was extracted from single individuals and PCR assays were conducted as described by Castillo et al. (2003). Moderate-to-low soil populations of these spiral nematodes were detected (5.5-11.5, 1.5-5.0 individuals/500 cm³ of soil, respectively). This prompted us to undertake a detailed morphological and molecular comparative study with previous reported data. Morphological and molecular analyses of females identified these species as Rotylenchus eximius Siddiqi, 1964, and Rotylenchus incultus Sher, 1965. The morphology of R. eximius females (five specimens studied) was characterized by having a hemispherical lip region clearly off set, with four to five annuli, body without longitudinal striations, lateral fields areolated in the pharyngeal region only, stylet 32 to 36 mm long, and broadly rounded tail. The morphology of R. incultus females (51 females and 16 males; Table 2) was characterized by a hemispherical lip region with the basal annulus subdivided by irregular longitudinal striations, with three, rarely four annuli; stylet 21.5 to 27.5 mm long, female tail hemispherical with terminus regularly annulated; phasmids anterior to anus level (3-6 annuli above). The morphology of the isolated nematodes agreed with previous descriptions of R. eximius (Siddiqi, 1964; Castillo and Vovlas, 2005) and R. incultus (Sher, 1965; Castillo and Vovlas, 2005; Vovlas et al., 2008), respectively. A single individual was used for DNA extraction. Primers and PCR conditions used in this research were specified in Cantalapiedra-Navarrete et al. (2013), and a single amplicon of 800, 1,100, and 450 bp was obtained and sequenced for D2 to D3, ITS1, and cytochrome c oxidase subunit 1 (coxI), respectively. Sequence alignments for D2 to D3 (KX669231-KX669233), ITS1 (KX669238-KX669240), and cox I (KX669244-KX669245) from R. eximius, showed 99% to 97%, 98% to 94%, 93% similarity to other sequences of R. eximius deposited in GenBank (EU280794-DQ328741, EU373663-EU373664, JX015401-JX015402, respectively). Similarly, D2 to D3 (KX669234-KX669237), ITS1 (KX669241-KX669243), and coxI (KX669246-KX669249) sequence alignments from R. incultus, showed 99%, 99% to 95%, 99% to 90% similarity, respectively, to other sequences of R. incultus deposited in GenBank (EU280797, EU373672-EU373673, JX015403, respectively). The best fitted model of DNA evolution was obtained using µ Model Test v. 2.1.7 (Darriba et al. 2012) with the Akaike information criterion. BI analyses were performed under the general time reversible (GTR) with invariable sites and a gamma-shaped distribution of substitution rates (GTR + I + G) model for ITS1 and coxI. Phylogenetic analyses of ITS1 and coxI using Bayesian inference (BI) placed R. eximius and R. incultus from Tunisia in subclades that included all R. eximius and R. incultus sequences deposited in GenBank (Fig. 1), which agrees with previous results (Cantalapiedra-Navarrete et al., 2013). Morphology, morphometry, and molecular and phylogenetic data obtained from these samples were consistent with R. eximius and R. incultus identification. To our knowledge, this is the first report of R. incultus in Tunisia. Consequently, all these data suggest that spiral nematode species of the genus Rotylenchus are predominant in olive as previously reported in other Mediterranean areas (Ali et al., 2014). [ABSTRACT FROM AUTHOR]