Among the natural products extracted from plants, tannins have been reported to possess antihelmintic properties especially for gastrointestinal nematodes in ruminants. Also, they are toxic to a wide range of fungi, bacteria and yeasts. Therefore, an in vitro and a glasshouse pot experiments were undertaken to evaluate the effect of chestnut tannins on the control of the root-knot nematode Meloidogyne javanica. In the in vitro experiment, different tannin concentrations in a geometric scale (from 0.32 to 20.48 g/l), were tested for their effect on hatching of the nematode, whereas in the pot experiment, 100, 250 and 450 g/m2 of tannins in aqueous solutions, were used in pots at transplant or at transplant and two weeks later for their effect on nematode control. In both experiments treatments were compared to untreated and fenamiphos-treated controls. In vitro a nematostatic effect of tannins was observed, whereas in the pot experiment a significant reduction of eggs and juveniles/g root, total population density and reproduction rates of the nematode were recorded. The anatomical changes induced by M. javanica in tomato roots treated with tannins did not differ from those produced by this and other Meloidogyne species on various hosts reported earlier.
Two experiments were carried out to assess the efficacy of different chemicals (azoxystrobin, fosthiazate, metham-sodium) and of the chitinolytic fungus Aphanocladium album (isolate MX-95), that could be alternatives to methyl bromide, against the soil borne pathogen Pyrenochaeta lycopersici and the root-knot nematode Meloidogyne incognita on tomato in a plastic house in southern Italy. In the first trial, the treatments were azoxystrobin (1.25 l a.i. /ha), fosthiazate (1.5 l a.i. /ha) and biological control agent Aphanocladium album isolate MX-95 (2.5 l/plot at 2×107 CFU/ml; plot surface 96 m2). In the second experiment, treatments were metham-sodium (1000 l c.p./ha) and A. album (5 l/plot at 1×107 CFU/ml). In both trials, chemicals and the fungus were applied by via sub-irrigation. Satisfactory control of the corky root and the root-knot nematode attack and a significant yield increase were obtained by application of azoxystrobin, fosthiazate and metham-sodium. A significant reduction of M. incognita soil population density occurred in plots treated with A. album. Also, high positive correlations were found between the symptoms caused on tomato roots by M. incognita and P. lycopersici.
The effect of Meloidogyne incognita race 1 at different population densities (0, 0.0625, 0.125, 0.25,... 256 eggs and juveniles/cm3 soil) on the growth of a rootstock (1103 Paulsen) and a cv. Italia of grapevine was studied in glasshouse experiment. One-year-old, self-rooted plants were transplanted into 1,200 cm3 plastic pots containing soil infested by M. incognita race 1 at different inoculum levels. Reproduction of M. incognita race 1 was significantly higher on cv. Italia than on the rootstock 1103 Paulsen. Tolerance limits (T) of 1.28 and 0.78 eggs and juveniles/cm3 soil were estimated respectively for 1103 Paulsen and Italia. Minimum relative plant growth of 0.55, 0.80 and 0.85, respectively for shoot length and node number increase and fresh top weight, were estimated for 1103 Paulsen; whereas values of 0.25, 0.50 and 0.60 were assessed for the cv. Italia. Nematode equilibrium density was 33.6 and 137.8 eggs and juveniles/cm3 soil, on 1103 Paulsen and Italia, respectively.
Suppressive effect of two composts, applied at five doses (0 %, 1 %, 2.5 %, 5 % and 10 % w/w), was studied on spring barley to control different genera of plant parasitic nematodes in potting mixtures. Amendment of soil with these materials resulted in a significant decreasing effect of plant parasitic nematode populations. The best reduction of number of plant parasitic nematodes was found for the nematode genera Bitylenchus, Helicotylenchus, Heterodera, Paratylenchus and Rotylenchulus by a municipal green compost (C1) and nematode genera Bitylenchus, Geocenamus, Helicotylenchus, and Rotylenchulus by a compost derived from penicillin production residues (C2). The compost C1 with a lower C:N ratio was more effective in the nematode control than the compost C2. The analysis of variance showed a significant interaction among all factors involved in the experiment: type of compost, different doses and nematode genera. Relationship between applied doses and number of nematodes showed a significantly high negative correlation.
N. Sasanelli, A. Anton, T. Takács, T. D’Addabbo, I. Birò and X. Malov
The effect of arbuscolar mycorrhizal fungi (AMF) on the nematicidal activity of Thymus vulgaris against the rootknot nematodes Meloidogyne incognita and M. javanica was investigated in two in vitro experiments. In the first experiment egg masses of M. incognita and M. javanica were immersed for 3 weeks in aqueous leaf extracts of thyme plants non-inoculated or previously inoculated with Glomus mosseae or mixed AMF strains (Sclerocystis sinuosa, Glomus claroideum-1, G. claroideum-2 and G. claroideum-3). Thereafter the hatching test continued in distilled water for five more weeks. In the second experiment egg masses of both Meloidogyne species were exposed to the different thyme extracts for 4, 8 and 16 hours and then incubated in distilled water for 8 weeks. Distilled water and 5 mg/ml aqueous solution of fenamiphos nematicide were used as controls. Numbers of second stage juveniles emerging weekly were expressed as cumulative percentages of the total egg content of the egg masses. In the first experiment juvenile emergence from eggs of both Meloidogyne species immersed in thyme extracts for three weeks was completely suppressed since the first week. Hatching of eggs of M. incognita in all the extracts was significantly lower than that in water control, although emergence in the extract from uninoculated thyme plants was significantly higher than the others and no statistical different from that of aqueous fenamiphos solution. Emergence of M. javanica juveniles was significantly lower after immersion in all the extracts than in distilled water control and aqueous fenamiphos solution. In the second experiment a 4-hour exposure to the extract from thyme inoculated with G. mosseae and mixed AMF population significantly reduced the final hatch of M. incognita in comparison to distilled water. A 16-hour exposure to the extract from mixed AMF inoculated plants resulted in a significantly lower egg hatch than the shorter exposure times, whereas no statistical difference was found between 4 and 8 hour exposure to both extracts. Emergence of M. javanica juveniles was statistically lower than in water only after 16 hours exposure to the extracts from mixed AMF strains inoculated plants, but no difference was found among the different exposure times. Growth of T. vulgaris was significantly increased only by the infections of mixed AMF strains.
N. Sasanelli, N. Vovlas, C. Cantalapiedra-Navarrete, G. Lucarelli, J. E. Palomares-Rius and P. Castillo
Severe infections of parsley plants and soil infestations with Meloidogyne javanica during an autumn surveys for the pathogenic root-knot nematode infestations were found in Monopoli at Bari province in Southern Italy. This unusual severe infection of parsley, considered a winter crop, was possibly instigated by a very warm autumn from the previous year. Nematodes were extracted from soil samples according to the Coolen’s method. Morphological analysis (based on stylet length, tail length and shape, adult females perineal pattern, excretory pore position and Ep/stylet ratio) and molecular studies were used for the nematode characterization and identification. In the soil of infested area a severely deformed root systems were observed, showing a galling rate = 2.5 - 4 (scale 0-5) and a soil nematode population densities ranging from 350 to 2,730 eggs and J2 per 5 g of fresh root. M. javanica attack on parsley roots is a limiting factor for plant growth. Considering that curly-leaf parsley varieties resistant to the nematodes are not yet available control strategies must be focused on reduction of soil infestation level below tolerance limit of the target nematode species. Due to the higher cost and reduced availability of fumigant and non-fumigant nematicides, soil solarization, organic amendments or biological control approaches should be preferably used as alternatives.
A pot experiment on potato was carried out to verify the nematicidal effect of four composts of different origin (C1: 70 % horse manure + 15 % sugar beet pomace + 5 % poultry manure + 10% grape pomace; C2: 100 % pig manure decomposed by juveniles of Musca domestica; C3: 100 % vermicompost from medical plants wastes; C4: 100% vermicompost from cattle manure) on the potato cyst nematodes G. rostochiensis (Ro1) and G. pallida (Pa2 and Pa3). Composts at different rates (1.0, 2.5 and 5.0 % w/w) were mixed with the nematode infested soils. Pots with unamended soils were used as control. Pots (4 l) were arranged in a glasshouse according to a randomized block design with four replications per each treatment. A significant reduction in number of cysts, eggs and juveniles/cyst and eggs and juveniles/g soil was observed in each compost in comparison to unamended soil. The suppressive nematode effect increased according to the compost NH4+ content and compost rate.
E. Abdel-Dayem, F. Erriquens, V. Verrastro, N. Sasanelli, D. Mondelli and C. Cocozza
The fertilizing and nematicidal effects of three organic amendments were evaluated in a pot experiment on melon plants infested by the root-knot nematode Meloidogyne
incognita. A soil artificially infested with 4 eggs and juveniles/ ml soil of the nematode was amended with: a) virgin olive pomace (VOP); b) composted olive pomace (COP); c) chicken manure based fertilizer (CM) and d) chicken manure based fertilizer combined with the biological control agent Paecilomyces lilacinus strain 251, brand name BioAct WG (CMB). VOP was applied at doses of 11 (VOP-A), 22 (VOP-B) and 44 t/ha (VOP-C); COP at 4.5 (COP-A), 9 (COP-B) and 18 t/ha (COP-C); CM at 3 t/ha and CMB at 3 t/ha combined with 4 kg/ha of BioAct WG. Untreated soil was used as control. The treatments CM, CMB, VOP-B and COP-B were established on the basis of N requirement of melon plants (120 kg/ha) taking into account soil and amendments N availability. Two weeks later amendment application and nematode inoculation, the soil was poured in 4.8 l clay pots which were arranged in a greenhouse according to a randomized block design with ten replications for each treatment. A one-month old melon seedling (cv. Galia) was transplanted in each pot and organic farming management practices were used during the growing period. At the end of the experiment, 60 days after transplant, plants were uprooted and height, fresh and dry shoot and root weights were recorded. Root gall index, on the roots, caused by the nematode attack, was estimated according to a 0–5 scale. Final nematode population density and reproduction rate were also calculated for each pot. All data were subjected to statistical analysis of variance (ANOVA) and means compared according to Least Significant Difference’s Test. Nematode population and root infestation were significantly suppressed by the addition of all amendments, compared to untreated control. However, CM and CMB resulted in a total more suppressive effect and in a significantly higher plant growth in comparison to all the other treatments. A significant correlation was found between root gall index and eggs and juveniles/g root and final nematode population density. No signifycant correlations were found between nematological parameters or plant growth parameters and amendment doses.
M. Renčo, N. Sasanelli, I. Papajová and L. Maistrello
Recently, tannins have been reported for their nematicidal activity against the root-knot nematode Meloidogyne javanica both in vitro and in pot experiments in addition to a biocidal effect on a wide range of fungi, bacteria and yeasts. However, no information is available on the effect of these polyphenols on plant parasitic cyst nematodes. Therefore, an in vitro and a pot experiments on potato were undertaken to investigate the nematicidal activity of tannin aqueous solutions at different concentrations on the potato cyst nematode Globodera rostochiensis. In the in vitro experiment different tannin concentrations in a geometric scale (from 0.32 to 20.48 g/l) were tested for their effect on the egg hatch of the nematode. All tested tannin concentrations were effective to reduce egg viability from 56 to 87%, in comparison to the untreated control. In the pot experiment, tannins, as aqueous solutions at rates of 100, 250 and 450 g/m2, were applied to soil at two different application times (at sowing and at sowing and two weeks later). All tested doses were effective to reduce the number of cyst/100 g soil, eggs and juveniles/g soil and reproduction rate in comparison to untreated control. The number of eggs and juveniles/cyst was not influenced by the different applied rates of tannins.
F. Jahanshahi Afshar, N. Sasanelli, S. Hosseininejad and Z. Tanha Maafi
The influence of ten initial population levels (0, 0.1, 0.2, 0.4, 0.8, 1.6, 3.2, 6.4, 12.8 and 25.6 second stage juveniles/cm3 soil) of Meloidogyne incognita and M. javanica on olive cultivar Zard growth was studied in two pot trials. Ten month old self-rooted olive cuttings were individually transplanted into 2 000 cm3 pot and inoculated with the defined initial populations, of both nematode species. Plants were grown in glasshouse for 13 months, then they were uprooted and plant growth (percent growth increase of main shoot length, number of nodes on main shoot, top and root fresh and dry weights and root length) and nematode parameters (root gall index, J2/g root, final nematode population density and reproduction rate Pf/Pi) were recorded. Results showed that cv. Zard was more susceptible to M. javanica than to M. incognita. A significant reduction of main shoot length growth 37.6 % and 10.7 % was observed at 0.1 and 12.8 juveniles/cm3 soil of M. javanica and M. incognita, respectively, in comparison to uninfested plants. Root systems of olive plants grown in M. incognita or M. javanica infested soils were galled within the gall index range 1.4–6. No significant differences were observed in the number of nodes on main shoot, top and root fresh weights and root dry weight at high levels of M. incognita Pi. A tolerance limit (T) of 0.4 juveniles/cm3 soil was estimated for olive plants cv. Zard to M. javania. The use of resistant olive rootstock or selected cultivars is recommended to minimize or to limit damage of nematode infections in nurseries and to prevent secondary attacks of soil borne plant pathogens especially Verticillium dahliae.