RESUMO

Leaf rust caused by Cerotelium fici (Cast.) Arth. is the main disease affecting Moraceae family plants, such as Ficus and Morus species (Galleti and Rezende 2016; Srikantaswamy et al. 2006). In August 2020, rust symptoms were observed in 100% of mulberry (Morus nigra L.) trees in an experimental orchard (Piracicaba, SP, Brazil; 22°42'28"S, 47°37'42"W). Mulberry leaves with high rust severity became yellowish and fell-off prematurely. Pustules were light brown with yellowish halo and presented mean size of 0.9 mm2. Uredinial paraphyses (n = 50) measured 42.2 ± 0.67 µm long with wall uniformly ca 0.6-1.1 µm thick. Urediniospores were brownish, echinulate, globoid to broadly ellipsoid, and measured 27.1 ± 0.29 × 21.0 ± 0.27 µm with a wall thickness of 0.6 ± 0.01 µm (n = 100). The morphology of the urediniospores observed in this study was similar to that reported in the literature for C. fici on Morus alba and Ficus spp. (Gupta et al. 1994; McKenzie 1986; Hennen et al. 2005). We used a low-coverage genome-skimming approach to retrieve genetic information of the rRNA cluster and the mtDNA. Genomic DNA was extracted from 3-4 mg of stored urediniospores at -80 °C, macerated in liquid nitrogen, using a modified cetyl trimethylammonium bromide extraction procedure (Lo Piccolo et al. 2012), and sequenced with 150-bp paired-end reads on Illumina NovaSeq 6000 System. Raw data, (45,761,957 X 2 reads) were assembled with SPAdes v3.15.1 (Bankevich et al., 2012) and the output used to create a custom BLAST database. Loci used for the phylogenetic analyses were identified by BLASTn using, as a query, sequences of C. fici from Ficus sp. from Australia publicly available: Accession No. MH047210.1 for the rRNA and MW036502.1 for COX3. The retrieved sequences were deposited in GenBank under accession numbers OM296992 and OP797407 for the partial rRNA cluster and COX3, respectively. The Bayesian inference phylogenetic analysis of the three concatenate loci (18S, 28S, and COX3) revealed that the isolate obtained in this study (MN1) was clustered in a well-supported clade with C. fici type species. Pathogenicity tests were conducted using mulberry potted plants under greenhouse conditions (25 ± 5 °C). The urediniospores suspension (5 × 104 urediniospores ml-1) with 0.05% Tween 20 was sprayed with an airbrush on fully expanded leaves until run-off. As a control, mulberry plants were sprayed with distilled water and kept under the same conditions. Inoculated and mock-inoculated plants were kept in a dark moist chamber at 23 °C (± 2 °C) for 24 h. After this period, plants were moved to the greenhouse. The experimental design was completely randomized with five replicates, each replicate consisted of one potted plant and the experiment was performed twice. At 12 days post-inoculation, all inoculated plants showed rust symptoms identical to those observed in the field, whereas control plants had no symptoms. The first symptoms were small pustules on the abaxial surface of fully expanded leaves. Small chlorotic lesions were observed on the adaxial leaf surface, which evolved into necrotic lesions. The pathogen was re-inoculated into potted plants, where it was maintained through monthly inoculations. To our knowledge, this is the first report of mulberry rust on M. nigra in Brazil. As mulberry leaves are the only natural food for silkworm (Bombyx mori L.), rust poses a significant threat to the sericulture industry because the disease can decrease production and quality of mulberry foliage.

RESUMO

The expansion of area under maize (Zea mays L.) and the use of no tillage have favored the incidence of stalk rot on this crop. The study aimed to evaluate the organic fertilizers and the treatment of corn seeds with Trichoderma spp. on the production of dry matter (DM) of shoot, incidence of stalk rot and corn yield. The experiment consisted in a factorial with split-plot in strips, on the randomized block design with four replicates, and the fertilization treatments (pig slurry; swine deep bedding; cattle slurry; mineral fertilizer; control treatment) were applied to the plots and the seeds treatment (with and without Trichoderma spp.) in the subplots. At the flowering stage, three corn plants per subplot were collected for the assessment of DM production. At physiological maturity stage, the incidence of stalk rot was assessed, and the ears of corn harvested for productivity assessment. The organic and mineral fertilizers increased the production of DM and productivity of corn. Trichoderma spp. increased the production of DM of corn, but had no reflection on productivity. The incidence of stalk rot in corn was higher in treatments with organic and mineral fertilization. Organic fertilizers increase dry matter production of shoot and corn yield, and Trichoderma spp. provides an increase in dry matter production of shoot.(AU)

A expansão da área cultivada com milho (Zea mays L.) e a utilização do plantio direto têm favorecido a incidência de podridões de colmo nessa cultura. O trabalho objetivou avaliar a adubação orgânica e mineral e o tratamento de sementes com Trichoderma spp. sobre a produção de matéria seca (MS) de parte aérea, incidência de podridões de colmo e produtividade de milho. O experimento constituiu-se em um fatorial com parcelas subdivididas em faixas, no delineamento blocos casualizados com quatro repetições, sendo os tratamentos de adubação (dejeto líquido de suínos; cama sobreposta de suínos; dejeto líquido de bovinos; adubação mineral e tratamento testemunha) aplicados nas parcelas e o tratamento de sementes (com e sem Trichoderma spp.) nas subparcelas. No estádio de florescimento foram coletadas três plantas de milho por subparcela para a avaliação da produção de MS da parte aérea. No estádio de maturação fisiológica, foi realizada a avaliação da incidência de podridões de colmo e a colheita das espigas para a avaliação da produtividade. Os adubos orgânicos e o mineral aumentaram a produção de MS e a produtividade de milho. Trichoderma spp. aumentou a produção de MS de milho, porém não teve reflexo sobre a produtividade. A incidência de podridões de colmo no milho foi maior nos tratamentos com adubação orgânica e mineral. Adubos orgânicos aumentam a produção de matéria seca de parte aérea e a produtividade de milho e Trichoderma spp. proporciona aumento na produção de matéria seca de parte aérea de milho.(AU)

Assuntos

RESUMO

The expansion of area under maize (Zea mays L.) and the use of no tillage have favored the incidence of stalk rot on this crop. The study aimed to evaluate the organic fertilizers and the treatment of corn seeds with Trichoderma spp. on the production of dry matter (DM) of shoot, incidence of stalk rot and corn yield. The experiment consisted in a factorial with split-plot in strips, on the randomized block design with four replicates, and the fertilization treatments (pig slurry; swine deep bedding; cattle slurry; mineral fertilizer; control treatment) were applied to the plots and the seeds treatment (with and without Trichoderma spp.) in the subplots. At the flowering stage, three corn plants per subplot were collected for the assessment of DM production. At physiological maturity stage, the incidence of stalk rot was assessed, and the ears of corn harvested for productivity assessment. The organic and mineral fertilizers increased the production of DM and productivity of corn. Trichoderma spp. increased the production of DM of corn, but had no reflection on productivity. The incidence of stalk rot in corn was higher in treatments with organic and mineral fertilization. Organic fertilizers increase dry matter production of shoot and corn yield, and Trichoderma spp. provides an increase in dry matter production of shoot.

A expansão da área cultivada com milho (Zea mays L.) e a utilização do plantio direto têm favorecido a incidência de podridões de colmo nessa cultura. O trabalho objetivou avaliar a adubação orgânica e mineral e o tratamento de sementes com Trichoderma spp. sobre a produção de matéria seca (MS) de parte aérea, incidência de podridões de colmo e produtividade de milho. O experimento constituiu-se em um fatorial com parcelas subdivididas em faixas, no delineamento blocos casualizados com quatro repetições, sendo os tratamentos de adubação (dejeto líquido de suínos; cama sobreposta de suínos; dejeto líquido de bovinos; adubação mineral e tratamento testemunha) aplicados nas parcelas e o tratamento de sementes (com e sem Trichoderma spp.) nas subparcelas. No estádio de florescimento foram coletadas três plantas de milho por subparcela para a avaliação da produção de MS da parte aérea. No estádio de maturação fisiológica, foi realizada a avaliação da incidência de podridões de colmo e a colheita das espigas para a avaliação da produtividade. Os adubos orgânicos e o mineral aumentaram a produção de MS e a produtividade de milho. Trichoderma spp. aumentou a produção de MS de milho, porém não teve reflexo sobre a produtividade. A incidência de podridões de colmo no milho foi maior nos tratamentos com adubação orgânica e mineral. Adubos orgânicos aumentam a produção de matéria seca de parte aérea e a produtividade de milho e Trichoderma spp. proporciona aumento na produção de matéria seca de parte aérea de milho.

Assuntos

RESUMO

Este trabalho teve por objetivo isolar, identificar e selecionar isolado(s) de Fusarium spp. em sementes de pepino e verificar a sua influência na qualidade fisiológica. Foram utilizados três sublotes e os tratamentos consistiram em: testemunha absoluta; BDA + manitol - 0,8Mpa; BDA; BDA + manitol - 0,8Mpa + fungo; e BDA + fungo. A qualidade fisiológica foi avaliada através de testes em laboratório e casa de vegetação. Cinco isolados de Fusarium verticillioides foram identificados e a sua transmissão através das sementes para plantas não foi possível afirmar. A técnica da restrição hídrica foi eficiente para proporcionar infecção das sementes, sabendo que e o fungo influencia negativamente na qualidade fisiológica das sementes de pepino da cultivar Caipira.

This research had the objective of isolate, identifying and select isolates (s) of Fusarium spp. in cucumber seeds and checking the influence of this (these) isolate(s) on the physiological quality. Three batches were used and treatments utilized consisted in: absolute witness; PDA + mannitol - 0.8Mpa; PDA pure; PDA + mannitol - 0.8Mpa + fungi; and PDA + fungi. The physiological quality was assessed by tests carried out in laboratory and greenhouse. Five isolates off Fusarium verticillioides were isolated and it was not possible to affirm its transmission through seed. The hydric restriction technique was efficient to provide the infection of cucumber seeds, since this fungus affected the physiological quality of cucumber seeds of this cultivar.