Quarenta e oito populações de Rotylenchulus reniformis foram recuperadas de amostras de solo e raízes de diferentes culturas e inoculadas em diferentes plantas hospedeiras, mantidas em microparcelas no Departamento de Fitossanidade da UNESP/FCAV, Campus de Jaboticabal, São Paulo. Os sintomas da doença causada pelo nematóide em algodoeiro (Gossypium hirsutum), no campo, foram documentados, bem como o hábito de parasitismo do nematóide em raízes de algodão e de mamoeiro (Carica papaya), utilizando-se de coloração in situ do nematóide com fuccina ácida. Efetuou-se a comparação morfológica de todas as populações, ao microscópio óptico composto, em montagens temporárias e, de algumas, ao microscópio eletrônico de varredura. Para as observações ao microscópio eletrônico de varredura, fêmeas adultas presas às raízes foram fixadas em glutaraldeído e pós-fixadas em tetróxido de ósmio, desidratadas em álcool etílico, secas em secador de ponto crítico, montadas, recobertas com 35 nm de ouro, observadas e elétromicrografadas em 15 kV. Os dados obtidos confirmam que R. reniformis é a única espécie do gênero distribuída nos agroecossistemas brasileiros e que a amplitude de variação de caracteres morfométricos em populações brasileiras desse nematóide, tais como comprimento do estilete, V % e forma da cauda, é maior que em populações da mesma espécie de outras regiões do mundo. Foram ilustradas fêmeas jovens de R. reniformis com a cauda bifurcada, e esse detalhe da morfologia do nematóide ainda não havia sido relatado.

The relationship of crops grown in rotation or in succession has increased every day and the use of antagonistic plants and/or non-host plants is one of the most efficient practices of integrated management of nematodes. This study aimed to evaluate the efficiency of crotalaria (Crotalaria spectabilis Roth) and millet [Pennisetum glaucum (L.) Leeke] ‘ADR 300’ in reducing the population of Meloidogyne incognita and M. javanica and in increasing the productivity of okra [Abelmoschus esculentus (L.) Moench] when cultivated in succession. The experiment was conducted in an area cultivating okra (host culture) in rotation, with a history of severe infestation by phytonematoids. The experimental design involved randomized blocks with six treatments and four replicates, with the following treatments: T1, 15 kg.ha-1 of millet seeds; T2, 30 kg.ha-1 of crotalaria; T3, 10 kg.ha-1 of millet + 20 kg.ha-1 of crotalaria; T4, 20 kg.ha-1 of millet + 6 kg.ha-1  of crotalaria; T5, 6 kg.ha-1 of millet + 36 kg.ha-1 of crotalaria; and T6, control. The nematode populations in the soil and roots were evaluated about 60 d after planting okra, and the yield was evaluated at the end of the crop cycle. Simple treatment with millet or crotalaria reduced the nematode population by 61% and 72%, respectively. The millet-crotalaria intercropping treatments reduced the nematode population by up to 85% compared with the control. In terms of productivity, there was an increase of 787 kg.ha-1 in the millet treatment and 2,109 kg.ha-1 in the intercropping treatments. Both the single cultivation of crotalaria or millet and the consortia of crotalaria and millet were effective in controlling the root-knot nematodes, and increased the productivity of okra.

Reaction of soybean cultivars to Meloidogyne javanica and Meloidogyne incognita Nematodes of the genus Meloidogyne are associated with soybean cultivation, unknown the reaction of cultivars. The objective of this work was to determine the reaction of soybean cultivars to M. javanica and M. incognita. Twenty-seven soybean cultivars were sown in plastic pots, in a completely randomized experimental design with eight replicates. Ten days after emergence of the seedlings, in a separate experiment, M. javanica and M. incognita were inoculated.

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Core Ideas Spatial distribution P. brachyurus nematode is influenced by soil chemical properties. In sites with low fertility the plants become more susceptible to nematode attack. In sites concentrating greater amount Mg are favorable to greater number of nematode. The economic damage to Brazilian soybean [Glycine max (L.) Merr.] production attributed to Pratylenchus brachyurus has increased in recent years. The objective of this study was to determine the influence of soil properties on nematode variability in a soybean crop. Soil and root samples (0–0.20 m) were collected from 142 points in an area that was 180 by 180 m. Root samples were analyzed for nematodes, and soil samples were analyzed for chemical attributes. The data were analyzed using principal component analysis and geostatistics. The spatial variability maps of the attributes S, Ca, Mg, K, sum of bases, base saturation index, and cation exchange capacity were aligned with the water runoff direction. Soil organic matter and K were associated with very low number of nematodes in the root (NNR) (NNR ≤ 3614), low (3614 < NNR ≤ 10,496), and moderate (10,496 < NNR ≤ 21,248). On the other hand, the regions with high Mg, S, and soybean productivity were associated with regions with high (21,248 < NNR ≤ 43,648) and very high (NNR > 43,648) NNR. The findings indicated that soil chemical characteristics influence the population dynamics of the root‐lesion nematode P. brachyurus.