Silicates have the potential to induce disease resistance in plants. Induction of nematode resistance usually results from paralysis of nurse cell development or activation of the hypersensitivity response. This study aimed to evaluate the effects of silicon (Si) treatment on the penetration and development of Meloidogyne javanica in various crops. The experiment was set up in a randomized (3 × 4) + 1 factorial design, with 3 Si sources (Silifort®, Rocksil® and wollastonite), 4 crops (maize, rice, common bean and soybean) and 1 treatment control (distilled water). The Si treatments included adding wollastonite to the soil 10 days prior to seedling transplantation, or spraying with solutions of Silifort® or Rocksil®, 2 days after seedlings transplantation. Twelve days after transplantation, the plants were inoculated with 1000 eggs and eventual second‐stage juveniles (J2) of M. javanica. At 3, 8, 13 and 18 days after inoculation (DAI), the plants were harvested and nematode penetration evaluated by optical microscopy. All Si treatments adversely affected development of M. javanica in soybean, common bean and rice and reduced nematode penetration of rice roots. Silifort® and wollastonite reduced nematode penetration in common bean and soybean roots, respectively. However, none of the Si treatments influenced the variables analysed in maize. The results of this study illustrate the potential of Si treatment to control M. javanica parasitism in plants.

Root-knot nematodes are responsible for significant tomato production losses and require taking integrated control measures. The aim of the current study is to evaluate the association between biological control and organic matter sources to Meloidogyne javanica control in tomato. In order to do so, two experiments were carried out under greenhouse conditions, in two different periods. Tomato plants were transplanted to pots and inoculated with 2,000 M. javanica eggs. Plants were treated with either Nem-Out™ or Compost-Aid ® biological control products, which were individually applied or in association with organic wastes such as poultry litter, filter cake, rice hull and coffee hull. Nematological and vegetative parameters were evaluated 60 days later. The treatments, except for Nem-Out™ + poultry litter and Compost-Aid ® + poultry litter, were efficient in reducing the number of galls. Treatment with Nem-Out™ + filter cake presented 83% gall reduction, whereas Compost-Aid ® + filter cake presented 98.5% reduction. The associations between Nem-Out™ + poultry litter and Compost-Aid ® + poultry litter did reduce the number of nematodes g -1 of root. Reduction in this parameter were observed for all others treatments, mainly when there was association between biological control (both, Nem-Out™ and Compost-Aid ® ) and organic wastes; the treatment with Nem-Out™ + coffee hull reduced by 96% the number of nematodes g -1 of root, whereas the one with Compost-Aid ® + filter cake reduced it by 97%. Most of the treatments have positively influenced the vegetative variables in comparison to the inoculated control.

Root-knot nematodes limit lettuce crop productivity. Efficient control is achieved through integrated management, and research about the efficiency of new products for nutrition and biological control is required. Thus, the objective of this study was to evaluate the effect of fertilizers, applied alone or in combination with microorganisms based product on the control of Meloidogyne javanica in lettuce. In the first research (research 1), conducted at two different periods, the products Agro-Mos®, Soil-SetTM and Copper-Crop® applied on shoots were evaluated; in research 2, the same products were applied isolated on shoots or associated to NemOutTM (Bacillus licheniformis, B. subtilis and Trichoderma longibrachiatum) applied to the soil. In research 1, the fertilizers Agro-Mos®, Soil-SetTM and Copper-Crop® applied alone promoted reduction in reproduction of M. javanica ranging from 31 to 75%, 36 to 79%, and 71 to 75%, respectively. The effect on plant development was variable, obtaining better results of fresh shoot mass applying Copper-Crop®. The combination of products did not have an additional effect on the control of the nematode, on the contrary, in general the products had antagonistic action. However, fertilizers and biological control applied isolated were efficient for nematode control.

Meloidogyne javanica and Pratylenchus brachyurus stand out among the main nematodes in soybean crops. Research on integrated management are often conducted, due to the low efficiency of the main control methods when they are applied alone. Thus, the aim of the present study was to assess the potential of biological control and plant nutrition products to control these nematodes in soybean. The effect of each product alone on nematode hatching and mortality was also assessed. A greenhouse experiment was also carried out, evaluating five doses of the product for biological control based on Bacillus and Trichoderma, with and without the presence of the product for nutrition, inoculated with 2000 eggs and juveniles for the gall nematode or 1000 specimens for the nematode lesions. After 30 days of multiplication, the aerial part was removed and the soil was revolved to receive the new sowing of the soybean with the respective treatments mentioned above. After 60 days, the experiments were evaluated for nematological parameters. Both products reduced hatching and increased nematode mortality. Treatments with biological control were efficient in reducing M. javanica and P. brachyurus, mainly when applied at doses close to 5 and 8 kg ha-1, respectively. The nutrition product negatively influences the biological control.

This work aimed to evaluate the host response of twelve wheat genotypes to Pratylenchus brachyurus and Meloidogyne javanica in two distinct periods. Tests were carried out in greenhouse with an initial population of 1,200 nematodes per pot, each containing 700 mL substrate and seven wheat seedlings. Evaluation was done at 60 and 83 days after inoculation in the first and the second experiment, respectively. At 60 days after inoculation with P. brachyurus, all cultivars were resistant to the nematode, presenting reproduction factor RF <1. At 83 days after inoculation, only the cultivars F. Cristalina and IPR 85 showed RF <1, the others were susceptible to the P. brachyurus. At 60 days after M. javanica inoculation, BRS Sabiá, F. Cristalina, IPR 144, IPR Catuara Tm, Quartzo and FPS Nitron presented RF> 1. At 83 days, cv. Gralha Azul, in addition to those already mentioned, presented RF>1. The cultivars BRS Gaivota and IPR 85 were susceptible to M. javanica in both experiments. It was concluded that the twelve wheat genotypes presented different host responses to the studied nematodes and most of them were susceptible.

Two series of polyurethane (PU) and carbon nanotubes (CNT) based composites with 0.0, 0.25, 0.5 and 1.0 mass% of CNT were obtained from diluting a commercial masterbatch with 30 mass% CNT and using two different dispersion methods. The quality of the dispersions was assessed using optical microscopy, and scanning and transmission electron microscopies. These tests showed that high controlled shear stress is necessary to produce composites with nanoscale dispersion: the elastic modulus improved by an average of 38% in the case of the high-shear dispersed materials in comparison with the neat polymer. A specific fatigue test conducted by dynamic mechanical analysis was first used in this work to compare the neat PU with the CNT/PU nanocomposites. The number of cycles to failure increased from 2700 for the neat polymer to 3200 for the 0.5 mass% CNT based nanocomposite; the elongation at failure increased by 145% in the test conditions.

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Summary Weeds have a great economic impact on agricultural production because they compete with crops for resources and are alternative hosts for pests, microbial pathogens and plant‐parasitic nematodes. This study aimed to investigate the susceptibility of weeds to the root‐knot nematodes Meloidogyne javanica and Meloidogyne incognita and assess the effect of aqueous weed extracts on M. javanica egg hatching. Four experiments were conducted, two for each nematode species. Weeds were inoculated with 2000 nematode eggs and grown for 60 days under greenhouse conditions. Soyabean cv. Monsoy 7110 was used as control. The weeds Ipomoea grandifolia, Solanum americanum, Digitaria horizontalis, Amaranthus deflexus, Sorghum halepense and Commelina benghalensis were susceptible to M. javanica and M. incognita in at least one experiment (reproduction factor, RF >1). Crotalaria juncea and Eleusine indica were susceptible to M. incognita in one experiment, and Digitaria insularis, Sida rhombifolia, Bidens pilosa, Urochloa decumbens, Crotalaria breviflora, Cenchrus echinatus, Crotalaria ochroleuca and Crotalaria spectabilis were immune or resistant (RF <1 or RF = 0). Alternanthera tenella, C. juncea, S. rhombifolia, C. ochroleuca, C. spectabilis, C. breviflora, B. pilosa, E. indica, U. decumbens and C. echinatus were resistant or immune to M. javanica (RF <1 or RF = 0). Compared with the control (water), all weed extracts reduced M. javanica egg hatch. Our results highlight the importance of weed control in agricultural systems, as nematodes can survive and multiply in weed roots during the off‐season. Weed leaves and shoots, however, may be an interesting source of compounds with nematicidal activity.