No abstract

Maize (Zea mays L.) is one crop of major relevance in Brazil; however, nematodes are limiting factors in maize growth and productivity due to the difficulty to control them. Studies point out that arbuscular mycorrhizal fungi (AMF) increase plant tolerance to nematodes. Thus, the aim of this study was to assess the association between AMFs and Pratylenchus brachyurus in maize growth. Six AMF species (Rhizophagus clarus, Claroideoglomus etunicatum, Gigaspora rosea, G. margarita, Scutellospora calospora, S. heterogama), as well as a control treatment free of mycorrhizae, were assessed under two different nematode inoculum conditions (presence and absence). Plants were collected and analyzed 60 d after inoculation. The nematode population was higher in the treatments inoculated with AMFs. On the other hand, just the plants inoculated with R. clarus did not present improved development in comparison to the control. Nematodes increased AMF spore density, but despite the fact that AMFs have presented different root colonization capacity (ranging from 2.3% to 95.0%), such capacity was not affected by the nematodes.

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.

Summary Nematodes of the genus Meloidogyne are one of the major limiting factors in tomato production and a challenging problem in organic systems. This study aimed to investigate the effect of agro-industrial wastes, their forms of application and doses on tomato plants inoculated with Meloidogyne javanica. First, nematodes were multiplied on tomato under glasshouse conditions to simulate a naturally infested environment. At 60 days after inoculation, plant shoots were removed, new seedlings were transplanted into the pots, and the soil was amended with agro-industrial wastes. Treatments were as follows: rice husk, common bean hull, soybean hull, orange bagasse, poultry litter and waste mixture (wastes mixed in equal proportions) applied in three different forms (raw, powdered and biodigester effluent). A non-treated control and a composted waste mixture were also assessed. At 60 days after transplanting, plants were evaluated for nematode parameters. Powdered bean hulls, soybean hulls, orange bagasse and waste mixture provided the best results and were selected for dose-response investigations. A second experiment was conducted in two periods using, in addition to the selected wastes, a mixture of powdered bean hulls, soybean hulls and orange bagasse. Wastes were applied at doses of 0 (control), 2, 4, 6 and 8 t ha−1. Powdered bean hulls, soybean hulls, orange bagasse and waste mixtures at 5 t ha−1 gave the best nematode control, with reductions of 55-100%. The optimal doses for vegetative growth were 4 t ha−1 in the first period and 5 t ha−1 in the second period.

No abstract

RESUMOA espécie Bauhinia forficata Link. apresenta rápido crescimento e altas taxas de sobrevivência no campo, no entanto, suas sementes apresentam desuniformidades na germinação, sendo esta característica desfavorável para produção de mudas em viveiros florestais. Nesse sentido, objetivou-se identificar métodos para superar a dormência, promovendo a germinação e o vigor de sementes da espécie B. forficata Link. As sementes foram colhidas da área do Horto Medicinal, localizado no município de Botucatu, e submetidas aos seguintes tratamentos: imersão em água destilada (25°C) por 24 horas, imersão em água destilada (25°C) por 48 horas, imersão em ácido sulfúrico (PA) por 5 minutos, imersão em acido acético (PA) por 2 horas, imersão em água destilada aquecida (65ºC) por 2 horas, imersão em água gelada (5ºC) por 2 horas, testemunha (sem nenhum tipo de tratamento) e escarificação mecânica. As sementes foram avaliadas quanto à porcentagem de germinação, índice de velocidade de germinação, condutividade elétrica e comprimento radicular. Houve diferenças entre os tratamentos para todos os parâmetros avaliados. A imersão em água por 48 horas foi o que propiciou os melhores resultados quanto a porcentagem de germinação 97,75%, índice de velocidade de germinação de 8,0, condutividade elétrica 71,5 mS.cm -1 . g -1 e comprimento de raiz de 8,60 cm. PALAVRAS-CHAVE: espécies florestais, germinação, planta medicinal.

Root-knot nematodes are among the major phytosanitary problems on vegetables, and the use of organic matter can be a viable method to control this parasite. Thus, in the present study we aimed to investigate in a greenhouse the use of bokashi doses (organic compound produced by fermentation of grain mixtures) in the control of Meloidogyne javanica in lettuce. Substrate infestation was carried out using tomato seedlings transplanted into pots containing 2 kg of autoclaved soil and inoculated with 2000 eggs and eventual second stage juveniles. After 60 days, the aerial part of the tomato plant was discarded and lettuce seedlings of cv. Vera were transplanted, adding bokashi at doses of 0, 5, 10 and 20 g/pot. One second treatment consisted in the application only at the time of transplant and another to reapply the same dosages in surface 15 days after transplanting. Forty-five (45) days after transplanting, vegetative (dry and fresh weight of aerial part) and nematological (galls and nematodes/g of root) parameters were evaluated. Doses close to 14 g/pot increased the vegetative growth and doses between 13 and 14 g/pot controlled the nematode. The application time did not affect the most of parameters studied.

The aim of this study was to assess the susceptibility of rice genotypes toPratylenchus brachyurusand investigate the inheritance of resistance in the crop. Two experiments were conducted under controlled conditions, using naturally infested soil. Twenty-six rice genotypes were assessed, with maize used to show the susceptibility pattern. The maize was cultivated for 90 days and the initial nematode population was determined. Then, rice genotypes were cultivated, and the final nematode population and the reproduction factor (RF) were estimated 90 days after germination. All genotypes were susceptible toP. brachyurusin the two experiments but only one showed statistical differences, indicating variation in susceptibility, and genotypes Linhagem L03-107 and Cateto Amarelo scored higher than the control genotype, with RF of 8.80 and 9.48, respectively. Inheritance of resistance was poorly influenced by genotype genetics. Cluster analysis allowed the identification of five different groups of genotypes but there was low genetic variability among the genotypes.