Growth and yield promoting effect of artificial mycorrhization combined with different fertiliser rates on field-grown tomato

Combination of plant inoculation with a commercial mycorrhizal formulation with half or full fertiliser application rates was evaluated for the effects on plant growth and yield and mycorrhization occurrence throughout two consecutive field tomato crops in southern Italy. Mycorrhizal formulation was inoculated on tomato seedling roots both in the nursery and after transplant. Inoculated tomato seedlings were significantly larger than non-inoculated seedlings less than 30 days after the first inoculation in the nursery. Above ground dry biomass and stem number of inoculated plants were found to be higher also at the end of each crop. Positive effects of mycorrhizal inoculation were extended also to marketable yield of both crops, mainly due to an increased number and weight of clusters and fruits. Mycorrhizal treatment also improved crop earliness, seen in terms of anticipating plant flowering, increasing first harvest yield, and reducing average harvesting time compared to non-inoculated plants. Both rates of mineral fertilisers positively affected tomato growth and marketable yield, but did not influence fruit quality parameters. No significant interaction was found between mineral fertilisation and plant mycorrhization. Crop inoculation with mycorrhizal formulations could reduce the amounts of fertilisers and pesticides being used, and could represent a sustainable technique to improve crop yield and profitability

Nematicidal Activity of Essential Oil from Lavandin (Lavandula × intermedia Emeric ex Loisel.) as Related to Chemical Profile

Essential oils (EOs) from lavandin are known for a large spectrum of biological properties but poorly and contrastingly documented for their activity against phytoparasitic nematodes. This study investigated the toxicity of EOs from three different lavandin cultivars, Abrialis, Rinaldi Cerioni, and Sumiens, either to juveniles (J2) and eggs of the root-knot nematode Meloidogyne incognita and to infective stages of the lesion nematode Pratylenchus vulnus. The suppressive activity of treatments with EOs from the three lavandin cultivars in soil infested by M. incognita was also investigated in a greenhouse experiment on potted tomato. The compositional profiles of tested EOs were also analyzed by GC-FID and GC-MS. Linalool was the major component of all the three EOs, as accounting for about 66%, 48%, and 40% of total EO from cv Rinaldi Cerioni, Sumiens, and Abrialis, respectively. Linalool acetate was the second most abundant compound in the EOs from cv Abrialis (18.3%) and Sumiens (14.9%), while significant amounts of camphor (11.5%) and 1,8-cineole (12.1%) were detected in cv Rinaldi Cerioni and Sumiens EOs, respectively. The mortality of M. incognita J2 peaked 82.0%, 95.8%, and 89.8% after a 24 h treatment with 100 mg·mL−1 solutions of cv Abrialis, Rinaldi Cerioni, and Sumiens EOs, respectively. Infective specimens of P. vulnus were largely more sensitive than M. incognita J2, as there were peak mortality rates of 65.5%, 67.7%, and 75.7% after 4 h of exposure to Abrialis, Rinaldi Cerioni, and Sumiens EO, respectively. All three lavandin EOs significantly affected also M. incognita egg hatchability, which reduced to 43.6% after a 48 h egg mass exposure to a 100 µg·mL−1 solution of cv Rinaldi Cerioni EO. Soil treatments with the three lavandin EOs strongly reduced, according to a dose–effect relationship, density of M. incognita eggs, and J2 both on tomato roots and in soil, as well as significantly reduced gall formation on tomato roots. Finally, almost all soil treatments with the lavandin EOs also resulted in a positive impact on tomato plant growth

Prodotti nematocidi di origine vegetale in orticoltura

Phytoparasitic nematodes cause heavy annual yield losses and thus can be considered among the most dangerous pests for a number of vegetable crops. Management of these parasites has been traditionally based on synthetic pesticides, but because of their high environmental impact we need to find more sustainable products to control nematodes. Biocidal compounds, naturally occurring as products of plant secondary metabolism, may represent a large source of biocompatible nematicides. This review briefly reports the main botanical groups and plant secondary metabolites with a nematicidal potential, as well as the most effective techniques for their exploitation. Nematotoxic volatile products, such as isothiocyanates and nitriles released from the degradation of glucosinolates present in tissues of Brassicaceae plants or cyanide deriving from the cyanogenic glucosides of some Sorghum species can be exploited for nematode control through the incorporation of fresh or dry plant material into the soil. Commercial liquid formulations based on seed oils from neem (Azadirachta indica Juss.) or sesame (Sesamum indicum L.) or water extracts from quillay (Quillaja saponaria Molina) bark or tagetes (Tagetes erecta L.) are already available for soil treatments over the crop cycle and/or seedling root dipping before t ransplant . Many plant species from Asteraceae family, such as Calendula spp., Chrysanthemum spp. and Artemisia spp., have been also demonstrated to be a potential source of nematicidal products for the control of root-knot and cyst phytonematodes economically relevant to vegetable crops. Green manures or crop rotations with indigenous (Medicago spp., Trifolium spp., Vicia spp., Lupinus albus) and tropical (Mucuna spp., Crotalaria spp) Leguminosae species, as well as soil amendments with their formulated plant biomass, have been reported to achieve a satisfactory nematode suppression, due to the high content of bioactive metabolites (phenols, alkaloids, alcohols and mainly saponins) of these plants. Essential oils from a wide range of aromatic and medicinal plants and their volatile bioactive components (terpenes, aldheydes, ketones and more) have been largely acknowledged for a high nematicidal activity, both in vitro studies and as soil treatments in water solution or by fumigation. Full exploitation of the high nematicidal potential of these products is strictly related to the development of technical formulations suitable to delay the release and degradation of active components into the soil. Phenolic compounds, such as terpenoids, flavonoids, tannins and coumarins, can also play a relevant role in the formulation of innovative nematicidal products. Commercial formulations of chestnut tannins demonstrated to be highly suppressive to root-knot nematode infestation. Nematicidal effect were reported also for soils amendments with tannin-rich plant materials. Coumarins are among the main agents of the strong nematicidal activity reported for plants from genus Ruta, such as R. graveolens and R. chalepensis. Susceptible of exploitation could be also the nematicidal properties reported for the pyrrolizidine and steroidal alkaloids from many Asteraceae, Leguminosae and Solanaceae species. Review of literature data confirmed the effectiveness of plant products for a sustainable phytonematode management, also due to the low environmental persistance and toxicity to humans, animal and plants of thei r act ive compounds. Multicomponent activity of most plant products also avoids the raising of nematode resistance, as frequently reported for repeated treatments with synthetic nematicides

Short-Time Impact of Soil Amendments with <i>Medicago</i> Plant Materials on Soil Nematofauna

Soil amendments with plant materials from Medicago species are widely acknowledged for a suppressive effect on plant-parasitic nematodes but their impact on beneficial components of soil nematofauna is still unknown. A study on potted tomato was carried out to investigate the short-time effects on the overall nematofauna of dry biomasses from six different Medicago species, i.e., M. sativa, M. heyniana, M. hybrida, M. lupulina, M. murex and M. truncatula, incorporated to natural soil at 10, 20, or 40 g kg−1 soil rates. All amendments resulted in a significant decrease of the total nematofauna biomass, whereas total abundance was significantly reduced only by M. heyniana, M. hybrida, and M. lupulina biomasses. Almost all the Medicago amendments significantly reduced the relative abundance of plant-parasites and root fungal feeders. All amendments significantly increased the abundance of bacterivores, whereas fungivores significantly increased only in soil amended with M. heyniana, M. lupulina and M. sativa plant materials. Mesorhabditis and Rhabditis were the most abundant genera of bacterivores, whereas Aphelenchoides and Aphelenchus prevailed among the fungivores. Predators were poorly influenced by all the tested Medicago biomasses, whereas the abundance of omnivores was negatively affected by M. heyniana and M. lupulina. Values of the Maturity Index and Sum Maturity Index were reduced by treatments with M. heyniana, M. hybrida, M. lupulina and M. sativa plant materials, whereas most of the tested amendments decreased values of the Channel Index while increasing those of the Enrichment Index. Enrichment and bacterivore footprints raised following soil addition with Medicago biomasses, whereas composite and fungivore footprints were significantly reduced. According to their overall positive effects on soil nematofauna, amendments with Medicago plant materials or their formulated derivatives could represent an additional tool for a sustainable management of plant-parasitic nematodes

Short-Time Impact of Soil Amendments with Medicago Plant Materials on Soil Nematofauna

Soil amendments with plant materials from Medicago species are widely acknowledged for a suppressive effect on plant-parasitic nematodes but their impact on beneficial components of soil nematofauna is still unknown. A study on potted tomato was carried out to investigate the short-time effects on the overall nematofauna of dry biomasses from six different Medicago species, i.e., M. sativa, M. heyniana, M. hybrida, M. lupulina, M. murex and M. truncatula, incorporated to natural soil at 10, 20, or 40 g kg&minus;1 soil rates. All amendments resulted in a significant decrease of the total nematofauna biomass, whereas total abundance was significantly reduced only by M. heyniana, M. hybrida, and M. lupulina biomasses. Almost all the Medicago amendments significantly reduced the relative abundance of plant-parasites and root fungal feeders. All amendments significantly increased the abundance of bacterivores, whereas fungivores significantly increased only in soil amended with M. heyniana, M. lupulina and M. sativa plant materials. Mesorhabditis and Rhabditis were the most abundant genera of bacterivores, whereas Aphelenchoides and Aphelenchus prevailed among the fungivores. Predators were poorly influenced by all the tested Medicago biomasses, whereas the abundance of omnivores was negatively affected by M. heyniana and M. lupulina. Values of the Maturity Index and Sum Maturity Index were reduced by treatments with M. heyniana, M. hybrida, M. lupulina and M. sativa plant materials, whereas most of the tested amendments decreased values of the Channel Index while increasing those of the Enrichment Index. Enrichment and bacterivore footprints raised following soil addition with Medicago biomasses, whereas composite and fungivore footprints were significantly reduced. According to their overall positive effects on soil nematofauna, amendments with Medicago plant materials or their formulated derivatives could represent an additional tool for a sustainable management of plant-parasitic nematodes

Nematicidal Activity of a Garlic Extract Formulation against the Grapevine Nematode <i>Xiphinema index</i>

The nematicidal activity of garlic extracts is known on root–knot nematodes but never investigated on the grapevine nematode Xiphinema index. In this study, the nematicidal activity of a commercial garlic extract formulate (GEF) was assessed on X. index, both in vitro and in a pot assay. In the in vitro assays, mixed specimens of X. index were exposed to a 0–4 mL L−1 range of GEF concentrations, checking nematode immotility and mortality after 2, 4 or 8 h. In the experiments on potted grapevines, plants cultivated in soil infested by X. index were irrigated twice at a 15-day interval with 0.05, 0.2 and 0.5 mL L−1 solutions of GEF, including nontreated soil as a control. An almost complete mortality of X. index specimens occurred after a 2 h exposure to a 2 mL L−1 GEF concentration, while an 8 h exposure to even the 0.0312 and 0.0156 mL L−1 solutions resulted in about 50% and 30% mortality, respectively. Soil treatment with a 0.5 mL L−1 GEF solution significantly reduced the population of X. index and increased the grapevine root growth compared to nontreated soil or soil treated with the lower dosages. Results of this study indicated that garlic-based nematicides could be an effective tool for X. index management in organic and integrated vineyards

Nematicidal Activity of a Garlic Extract Formulation against the Grapevine Nematode Xiphinema index

The nematicidal activity of garlic extracts is known on root&ndash;knot nematodes but never investigated on the grapevine nematode Xiphinema index. In this study, the nematicidal activity of a commercial garlic extract formulate (GEF) was assessed on X. index, both in vitro and in a pot assay. In the in vitro assays, mixed specimens of X. index were exposed to a 0&ndash;4 mL L&minus;1 range of GEF concentrations, checking nematode immotility and mortality after 2, 4 or 8 h. In the experiments on potted grapevines, plants cultivated in soil infested by X. index were irrigated twice at a 15-day interval with 0.05, 0.2 and 0.5 mL L&minus;1 solutions of GEF, including nontreated soil as a control. An almost complete mortality of X. index specimens occurred after a 2 h exposure to a 2 mL L&minus;1 GEF concentration, while an 8 h exposure to even the 0.0312 and 0.0156 mL L&minus;1 solutions resulted in about 50% and 30% mortality, respectively. Soil treatment with a 0.5 mL L&minus;1 GEF solution significantly reduced the population of X. index and increased the grapevine root growth compared to nontreated soil or soil treated with the lower dosages. Results of this study indicated that garlic-based nematicides could be an effective tool for X. index management in organic and integrated vineyards

Biostimulants for Plant Growth Promotion and Sustainable Management of Phytoparasitic Nematodes in Vegetable Crops

The parasitism of root-knot nematodes, Meloidogyne spp., can cause heavy yield losses to vegetable crops. Plant biostimulants are often reported for a side-suppressive effect on these pests and many commercial products are increasingly included in sustainable nematode control strategies. Source materials of most biostimulants derived from plant or seaweed raw materials were documented for a reliable suppression of root-knot nematode species, whereas the suppressiveness of microbial biostimulants was found largely variable, as related to the crop and to environmental factors. Chitosan-based biostimulants were also stated for a variable phytonematode suppression, though clearly demonstrated only by a few number of studies. In a preliminary experimental case study, four commercial biostimulants based on quillay extract (QE), sesame oil (SO), seaweeds (SE), or neem seed cake (NC) were comparatively investigated for their effects against the root-knot nematode M. incognita on potted tomato. Soil treatments with all the four biostimulants resulted in a significant reduction of nematode eggs and galls on tomato roots, though NC and SO were significantly more suppressive than QE or SE. In addition, almost all biostimulant treatments also resulted in a significant improvement of tomato growth compared to the non-treated control. These preliminary results seem to confirm the literature data and clearly indicate the potential role of biostimulants for a safe nematode management both in organic and integrated crop systems

ATTIVITA’ NEMATOCIDA DI OLI ESSENZIALI DI IBRIDI DI LAVANDA

I nematodi fitoparassiti sono responsabili di perdite rilevanti per la produzione di numerose colture agrarie di rilievo economico, causa l’ampia diffusione e la polifagia delle specie più dannose. Gli oli essenziali di molte “aromatiche” appartenenti alla vasta famiglia botanica delle Lamiaceae hanno già dimostrato di possedere un’elevata attività nematocida e, quindi, un ampio potenziale d’impiego nella preparazione di formulati a maggiore sostenibilità ambientale rispetto ai prodotti nematocidi di sintesi (Isman, 2000; Andrés et al., 2012). Tra le lamiacee, il lavandino (Lavandula hybrida Rev.) occupa un ruolo di rilievo nel mercato mondiale degli aromi e fragranze, dato che i suoi oli essenziali (O.E.), estratti dagli apici fiorali di un gran numero di cultivars, trovano largo impiego nell’industria di saponi, profumi, cosmetici, ecc. Recenti sviluppi nella ricerca sugli O.E. di lavandino ne hanno inoltre dimostrato le proprietà analgesiche, antinfiammatorie, sedative ed antibatteriche, correlate al contenuto dei due maggiori costituenti di tali oli, il linalolo ed il linalil acetato (Lis-Balchin e Hart, 2002). Obiettivo di questo lavoro è stato uno studio preliminare sull’attività nematocida degli O.E. di quattro differenti cultivars di lavandino: Alba, Abrialis, RC (Rinaldi Ceroni) e Sumiens, nei confronti di due nematodi fitoparassiti di grande rilevanza economica, quello galligeno Meloidogyne incognita ed il nematode delle lesioni radicali Pratylenchus vulnus (Perry et al., 2009)

Long Time Effect of Soil Solarization Integrated with Dazomet or Chicken Manure on Yield, Weeds and Root-Knot Nematodes in Tomato and Melon

Effects of 5-week soil solarization, either alone or combined with dazomet or a chicken manure compost, on tomato and melon yield, root-knot nematode infestation and weeds were investigated along three crop cycles in a plastic greenhouse infested by Meloidogyne javanica in Southern Italy. Solarization treatment, either alone and combined with dazomet or organic amendment, always resulted in a significant increase of marketable crop yield, and its effect lasted up to two years from the treatment. Nematode population indices and number of root galls were always lower in solarized soil than in untreated control. Organic amendment alone suppressed soil nematode population only in the first two crop cycles, though less than solarization and with no significant reduction of gall formation. Dazomet alone resulted in a yield increase only in the first tomato crop, with no significant reduction of soil nematode density and root galls. Solarization treatment completely suppressed the emergence of all the annual and perennial weed species, though C. rotundus was controlled only immediately after the treatment. Suppressivity of SOL on annual weeds and the perennial C. dactylon was extended to the tomato and melon crop following the treatment, but persisted on D. sanguinalis and P. oleracea, also in the third crop. Combination of solarization with dazomet or chicken manure compost did not enhance the suppressive effect on weeds. Solarization confirmed to provide an effective suppression of root-knot nematodes and weeds in the greenhouse vegetable crop systems of warm climate regions, with no need to be combined with other control tools