This study was carried out to select Trichoderma isolates from Amazon forest soil samples, identify their potential for sheath blight (Rhizoctonia solani) suppression in rice, and promote plant growth. Four out of the 13 isolates (T.06, T.09, T.12, T.52) which showed in vitro potential were evaluated through assays under greenhouse conditions utilizing four application methods: 1) preventive and curative sprays; 2) seed treatment + curative sprays; 3) seed treatment; 4) substrate treatment. These four isolates also showed reduced R. solani mycelial growth and sclerotial viability (>50%) and were positive for phosphate solubilization and cellulose degradation. They significantly reduced sheath blight severity when applied as seed treatment, substrate incorporation or foliar spray. However, the preventive and curative sprays were the most efficient method, reducing sheath blight severity by 43% and the area under the disease progress curve by 45%. Isolates T.12 and T.52 applied in substrate treatment increased aerial and root dry weight by 61.2 and 32.9%, respectively. These two isolates showed potential as growth stimulants and can be used as novel biological products and bioinoculants in agriculture for increasing grain yield. RESUMO: Foi realizada a seleção de isolados de Trichoderma spp. provenientes de amostras de solo da Floresta Amazônica e identificado o seu potencial para suprimir a queima da bainha (QB) (Rhizoctonia solani) e para promover o crescimento de plantas de arroz. Quatro de 13 isolados (T.06, T.09, T.12, T.52) que mostraram potencial in vitro foram avaliados em experimentos em casa de vegetação, utilizando-se quatro métodos de aplicação: 1) pulverização preventiva e curativa; 2) tratamento de semente + pulverização curativa; 3) tratamento de semente; 4) tratamento do substrato. Esses quatro isolados, in vitro, reduziram o crescimento micelial de Rhizoctonia solani e a viabilidade do escleródio (>50%), sendo positivos para solubilização de fósforo e degradação da celulose. Em casa de vegetação, os quatro isolados reduziram significativamente a severidade da QB quando aplicados via tratamento de semente, incorporados ao substrato e por pulverização foliar. Entretanto, a pulverização preventiva + curativa foi mais eficiente, reduzindo em 43% a severidade da QB e em 45% a área sob curva de progresso da doença. Os T.12 e T.52 aplicados via substrato promoveram o incremento em massa seca da parte aérea e radicular em 61,2 e 32,9%, respectivamente. Esses dois isolados mostraram potencial como promotores do crescimento e poderão ser usados como novo produto biológico e bioinoculantes na agricultura para aumento de produtividade. Rice sheath blight biocontrol and growth promotion by Trichoderma isolates from the Amazon Biocontrole da queima da bainha em arroz e promoção do crescimento por isolados de Trichoderma da Amazônia

Crop damage by rice sheath blight, Rhizoctonia solani, can decrease rice yield by up to 45 %. The classical control method of rice sheath blight in the Amazon region is the application of fungicides. Therefore, we tested here the efficiency of a biocontrol agent, Trichoderma asperellum, and fungicides. Two experiments of rice cultivation were carried out with seven treatments: four isolates of T. asperellum, a mixture of the four isolates, the fungicide pencycuron, and the control. The first experiment involved a randomized block design, and seed and foliar spray on all plots. The second experiment involved a split-plot design with foliar spray in main plots and the 1-2 foliar sprays in subplots. Results show that all treatments reduced sheath blight progression rate. In the randomized block experiment T. asperellum reduced disease severity by 19 %, increased grain weight by 34 %, and increased yield by 41 %. In the split-plot design experiment, the mixture of the four T. asperellum isolates grain reduced disease severity by 26 %, increased grain weight by 18.5 %, and increased yield by 26 %. Our results show for the first time that a mixed isolates of T. asperellum was efficient in reducing disease severity and increasing yield and grain weight.

Internal and external seedborne fungal pathogens of Anadenanthera macrocarpa reduced seedling emergence and the quality of seedlings grown from contaminated seeds. Colletotrichum gloeosporioides, Fusarium lateritium, F. semitectum, Pestalotiopsis sp. and Phomopsis dalbergiae were the only fungi consistently isolated from seed samples collected from afforestation companies, university forestry departments and a Forest Reserve Park. Their frequency was much lower in surface disinfested than in untreated seeds. The temporal dynamics of the pericarp and seed infection on trees used for seed harvest in the Forest Reserve Park showed that colonization by these fungi starts soon after pod and seed formation, and continues to increase to pod maturity. Although the maximum proportion of infected seeds occurred at full maturity, their proportion was also high at physiological maturity. The high external seed infestation appears to occur during on-floor sun drying of the pods and separation of pericarps from seeds by broom sweeping. All five fungi were highly pathogenic to seeds and seedlings, causing seed rot, root rot and reduced height and thriftiness of surviving seedlings. Our results explain the heavy losses suffered by nurserymen due to low quality seedlings. This is the first report of the occurrence of these fungi on this host causing economical losses.

-Soil solarization is a technique used for weed and plant disease control in regions with high levels of solar radiation. The effect of solarization (0, 3, 6, and 9 weeks) upon weed populations, carrot (Daucus carota L. cv. Brasília) yield and nematode infestation in carrot roots was studied in São Luís (2 o 35' S; 44 o 10' W), MA, Brazil, using transparent polyethylene films (100 and 150 µm of thickness). The maximum temperature at 5 cm of depth was about 10 o C warmer in solarized soil than in control plots. In the study 20 weed types were recorded. Solarization reduced weed biomass and density in about 50% of weed species, including Cyperus spp., Chamaecrista nictans var. paraguariensis (Chod & Hassl.) Irwin & Barneby, Marsypianthes chamaedrys (Vahl) O. Kuntze, Mitracarpus sp., Mollugo verticillata L., Sebastiania corniculata M. Arg., and Spigelia anthelmia L. Approximately 40% of species in the weed flora were not affected by soil mulching. Furthermore, seed germination of Commelina benghalensis L. was increased by soil solarization. Marketable yield of carrots was greater in solarized soil than in the unsolarized one. It was concluded that solarization for nine weeks increases carrot yield and is effective for controlling more than half of the weed species recorded. Mulching was not effective for controlling root-knot nematodes in carrot.Index terms: Commelina benghalensis, Cyperus, organic farming, soil heating, mulching, plastic film covers, soil desinfection, nematode controls, sandy soil. SOLARIZAÇÃO DO SOLO PARA O CONTROLE DE PLANTAS DANINHAS NA CULTURA DE CENOURARESUMO -A solarização é uma técnica usada para o controle de plantas daninhas e doenças de plantas em regiões de alta radiação solar. Estudou-se o efeito da solarização (por 0, 3, 6 e 9 semanas) sobre a população de plantas daninhas, a produção de cenoura (Daucus carota L. cv. Brasília) e a infestação das raízes por nematóides. O experimento foi realizado em São Luís, MA, utilizando filmes de plástico com espessuras de 100 e 150 µm. A temperatura máxima a 5 cm de profundidade foi cerca de 10 o C maior nas parcelas solarizadas do que nas testemunhas. Havia 20 tipos de ervas daninhas no experimento. A solarização reduziu a biomassa e densidade das plantas daninhas em 50% das espécies, incluindo Cyperus spp., Chamaecrista nictans var. paraguariensis (Chod & Hassl.) Irwin & Barneby, Marsypianthes chamaedrys (Vahl) O. Kuntze, Mitracarpus sp., Mollugo verticillata L., Sebastiania corniculata M. Arg. e Spigelia anthelmia L. No entanto, foi ineficaz para o controle de 40% das espé-cies vegetais presentes no campo. Além disso, a solarização estimulou a germinação das sementes de Commelina benghalensis L. O rendimento comercial da cenoura foi maior nas parcelas solarizadas do que naquelas não cobertas. Conclui-se que a solarização por nove semanas aumenta o rendimento da cenoura e foi eficiente para o controle de mais da metade das espécies de plantas daninhas no campo. Porém, a cobertura de plástico foi ineficiente para o controle de nematóide...

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The application of Trichoderma fungus can be used to obtain seedlings of higher quality for plantations. The objective of this study was to evaluate the effects of Trichoderma isolates on the germination and initial growth of açaí seedlings. Two trials were set up. In the laboratory, the seeds were inoculated in suspensions prepared with each of the isolates for 24 h, and they were arranged in trays containing filter paper in a completely randomized design with five replicates containing 50 seeds each. For the control, the seeds were submerged only in water. Part of the seedlings resulting from seeds treated and not treated with Trichoderma were transferred to bags containing forest soil and were submitted to seven modes of application of Trichoderma and kept in a nursery. The speed of germination and hypocotyl were not influenced by the biological treatment. The application of the different Trichoderma isolates positively influenced the height, collar diameter, number of leaves, root size, leaf area and root, and aerial part dry mass of the açaí seedlings. The application of the Trichoderma isolate TAM01 on the preplanting substrate and biweekly applications on the postplanting substrate was the combination that most positively influenced the development of açai seedlings.

Enterolobium schomburgkii (monkey ear) is important Amazonic forest specie, being used for wood and medicinal purposes and environmental recuperation issues. Biological treatment such as Trichoderma fungus is alternative method that may improve performance of seeds germination and provide healthy seedlings. We aimed to assess effect of Trichoderma fungus on development of E. schomburgkii seedlings. Five isolates of Trichoderma spp., in the concentration of 1.0 x 107 conidia.mL-1, were assessed and applied through four methods: seeds; pre-planting substrate; post-planting substrate; and seed + pre-planting + post-planting substrate. The seedlings were produced in polypropylene bags and kept in nursery for 10 months. The experimental design was completely randomized, in a 5x4+1 factorial scheme, with 10 repetitions. We monthly assessed the plant height, collar diameter and number of leaves and leaflets. After 10 months, we assessed root length, dry matter of aerial part and dry matter of roots system. The results showed that variables were significantly influenced by Trichoderma isolates and its application modes, either individually or under interaction, except on the root length. Eight treatments boosted the plants height and five of them increased the collar diameter, compared with the control. The height of the seedlings was the variable that mostly influenced by the treatments. Application of Trichoderma in pre-planting substrate influenced the highest number of variables analyzed. Therefore, the isolates application used in this work is feasible for production of Enterolobium schomburgkii seedlings. Based on results of this experiment we do not recommended treatment of Enterolobium schomburgkii seeds with Trichoderma isolates, except using T. asperellum T09

Trichoderma is a beneficial fungus that can be used in both the control of phytopathogens and in promoting germination and plant growth. Thus, this study aimed to evaluate the effect of five Trichoderma isolates (T09, T12, T52, Tc and Tce) in seven different application modes on seeds and seedlings of the Khaya ivorensis A. Chev. (African mahogany). Fungi applications were tested by microbiolization of the seeds, in the pre-planting substrate, by monthly applications in the seedlings and in four combinations of these three treatments. Under laboratory conditions, the germination, germination speed index (GSI), and radicle and hypocotyl lengths were evaluated in seeds, treated and untreated, with Trichoderma. In the nursery, it was evaluated the height, root collar diameter, number of leaflets, root length, and the dry weight of root system and aerial part in seedlings with different forms of Trichoderma application. Trichoderma isolates did not influence germination percentage, GSI and radicle length. The fungus application methods in the K. ivorensis seedlings increased the height and leaflets number of the plants by at least one of the Trichoderma isolates tested in this study.Trichoderma spp. e seus efeitos na qualidade fisiológica das sementes e no desenvolvimento de mudas de mogno africano RESUMO: Trichoderma é um fungo benéfico que pode ser utilizado tanto no controle de fitopatógenos como na promoção da germinação e do crescimento de plantas. Assim, objetivou-se avaliar o efeito de cinco isolados de Trichoderma (T09, T12, T52, Tc e Tce), em sete modos de aplicação, sobre sementes e mudas de Khaya ivorensis A. Chev. (mogno africano). Foram testadas aplicações dos fungos via microbiolização das sementes, no substrato pré-plantio, em aplicações mensais nas mudas e, em quatro combinações desses três tratamentos. Em condições de laboratório foram avaliados a germinação, índice de velocidade de germinação (IVG) e, o comprimento da radícula e hipocótilo, em sementes tratadas e não tratadas com Trichoderma. Em viveiro, avaliou-se altura, diâmetro do coleto, número de folíolos, comprimento da raiz e, a massa seca da parte aérea e sistema radicular em mudas com as diferentes formas de aplicação de Trichoderma. Os isolados de Trichoderma não influenciaram a porcentagem de germinação, o IVG e o comprimento da radícula. Os modos de aplicação dos fungos avaliados nas mudas de K. ivorensis aumentaram a altura e o número de folíolos das plantas, por pelo menos um dos isolados de Trichoderma testado neste trabalho.Palavras-chave: tratamento biológico; sementes florestais; fungos; promoção de crescimento; Khaya ivorensis Trichoderma spp. and its effects on seeds physiological quality and seedlings development of African mahogany Rev. Bras. Cienc. Agrar., Recife, v.15, n.1, e5843, 2020 2/7