Summary Aphelenchoides besseyi is a concern to Brazilian agriculture, since the losses caused by the green stem and foliar retention syndrome in soybean, especially in hot and humid climates, could reach high levels. However, limited information is available regarding the host-parasite relationship. The objective of this study was to evaluate the capacity of A. besseyi to penetrate soybean roots and its movement in soybean tissues until reaching the top parts. Plants inoculated with 1000 A. besseyi were evaluated for root penetration from 1-28 days after inoculation (DAI), and post-penetration and movement inside tissues by staining them with acid fuchsin. Plant development, chronology of the symptoms and the number of pods were also evaluated at 60 DAI. Aphelenchoides besseyi was found in the cortex and xylem vessels of roots from 1 DAI. During the experimental period, the number of nematodes from roots to shoots increased more than 123, 330 and 430%, respectively, for roots, stems + petioles + inflorescences, and leaves, demonstrating the ascendent movement of A. besseyi. Necrotic lesions in young leaves and apical tissues were observed from 8 DAI; the typical symptom of ‘amachamiento’ was observed from 10 DAI, with enlargement of nodes and lesions in inflorescences and, at 30 DAI, stunted plants were detected. At 60 DAI, inoculated plants had lower numbers of pods and exhibited severe symptoms including abortion of flowers and tissue splitting and cortical lesions in a few pods and roots. These observations emphasise the importance of A. besseyi for Brazilian soybean production.

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Estudos com épocas de semeadura são importantes ferramentas no processo de adaptação e estabilidade de híbridos de canola. O objetivo em realizar este trabalho foi avaliar os subperíodos: emergência ao início do florescimento (EIF), duração do florescimento (DFL), duração da maturação (DMA) e ciclo, bem como o desempenho agronômico de híbridos de canola em diferentes épocas de semeadura. O experimento foi conduzido no Paraná entre 07/04/ e 25/10/2018, num delineamento de blocos casualizados com quatro repetições em esquema de parcelas subdividas. As parcelas foram compostas por seis épocas de semeadura (07 e 22/04, 07 e 22 /05 e 06 e 21/06) e as subparcelas por cinco híbridos de canola (Hyola 50, Hyola 61, Hyola 433, Hyola 571 CL e Hyola 575 CL). Os híbridos Hyola 50 e Hyola 61 apresentaram os maiores subperíodos EIF, DFL, DMA e ciclo. Todavia, atrasar a época de semeadura reduziu os subperíodos de todos os híbridos. A maior produtividade foi obtida com Hyola 50, Hyola 61 e Hyola 433, respectivamente. À medida que atrasou a semeadura, houve redução na massa de mil grãos, produtividade e teor de óleo. Independente do hibrido, o melhor intervalo de semeadura foi entre 07/04 e 22/04 e as melhores respostas agronômicas foram obtidas pelos híbridos Hyola 50, Hyola 61 e Hyola 433.

The use of non-host cover crops is a key strategy for controlling root-knot nematodes in infested fields. However, pathogenicity of nematodes to cover crops may vary between populations and localities. This study assessed the response of green manure species and millet (Pennisetum glaucum (L.) R.Br.) cultivars to four populations of Meloidogyne javanica (denominated Mj-2, Mj-3, Mj-6 and Mj-7). Seedlings of radish (Raphanus sativus L.), pigeon pea (Cajanus cajan (L.) Huth) 'IAPAR 43', buckwheat (Fagopyrum esculentum Moench) 'IPR 92-Altar' and millet 'BRS 1501', 'ADR 300' and 'ADR 500' were inoculated with 1000 eggs and second-stage juveniles of M. javanica. Soybean (Glycine max (L.) Merr.) 'M6210 IPRO' was used as control. At 60 d after inoculation, plants were evaluated for root fresh weight, gall index (GI), number of nematodes per gram of root and reproduction factor (RF). For GI, Mj-3 and Mj-6 were the most aggressive to soybean (GI = 5.0). In pigeon pea, Mj-7 resulted in the highest GI (3.5). Radish had the lowest GI (0.67) with Mj-2. For buckwheat, Mj-3 was the most aggressive population, with a GI of 4.50. Mj-3 and Mj-7 resulted in the highest GI in 'ADR 300', and Mj-6 and Mj-7 in 'ADR 500'. The reproductive ability of nematode populations differed between hosts. Mj-2 was the most pathogenic to 'ADR 300' (RF = 10.88), Mj-3 to buckwheat (RF = 53.46) and radish (RF = 4.81), Mj-6 to 'ADR 500' (RF = 19.58) and Mj-7 to pigeon pea (RF = 2.99) and 'BRS 1501' (RF = 15.05). Soybean was susceptible to all M. javanica populations (RF = 33.69 to 257.22). Green manure species and millet cultivars varied in their responses to M. javanica populations of different origins.

Root lesion nematodes limit the productivity of several crops of economic importance, requiring alternatives for their management. Resistance inducers activate enzymes involved in defense mechanisms and micronutrients can influence this process by acting as enzymatic cofactors. Thus, the objective of this study was to evaluate the effect of foliar application of a commercial organomineral fertilizer and its association or not with zinc (Zn) and manganese (Mn) micronutrients on the Pratylenchus brachyurus suppression and soybean plant development under greenhouse conditions. Shoots of soybean were treated 10 days after germination and inoculated with 5000 nematodes/plant five days after the treatments, using untreated plants as controls. Treatments consisted of a commercial product based on phosphorylated mannanoligosaccharide derived from the cell wall of Saccharomyces cerevisiae (here coded as MOS), Zn, Mn, MOS+Zn, MOS+Mn or MOS+Zn+Mn. At sixty days after establishment of treatments, the plants were collected and evaluated for vegetative analysis, nematological analysis and nutrient contents. The work was repeated at different times: experiment 1 from November 2016 to January 2017 and experiment 2 from October to November 2017. All treatments were efficient in controlling P. brachyurus in at least one of the evaluated nematological parameters, compared to the control. However, only the plant spraying with MOS+Zn results in significative reduction of the total number of nematodes and the number of P. brachyurus nematodes per gram of soybean root in both experiments. In addition, spraying of plants with Mn increased shoot dry weight and all treatments resulted in higher concentrations of copper, Zn and Mn in soybeans leaves compared to control.