The objective of this study was to evaluate the competitiveness of two cultivars of upland rice drought-tolerant, cultured in coexistence with weed S. verticillata, under conditions of absence and presence of water stress. The experiment was conducted in a greenhouse at the Experimental Station of the Universidade Federal de Tocantins, Gurupi-TO Campus. The experimental design was completely randomized in a factorial 2 x 2 x 4 with four replications. The treatments consisted of two rice cultivars under two water conditions and four densities. At 57 days after emergence, were evaluated in rice cultivars and weed S. verticillata leaf area, dry weight of roots and shoots and total concentration and depth of roots. Was also evaluated in rice cultivars, plant height and number of tillers. Water stress caused a reduction in leaf area, the concentration of roots and vegetative components of dry matter (APDM, and MSR MST) of rice cultivars and Jatoba Catetão and weed S. verticillata. The competition established by the presence of the weed provided reduction of all vegetative components (MSPA, and MSR MST) of cultivars and Jatoba Catetão. It also decreased the number of tillers, the concentration of roots and leaf area. At the highest level of weed competition with rice cultivars, a greater decrease in vegetative components and leaf area of culture, regardless of water conditions.

The galling insect Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae) is a major limiting factor in the cultivation of drought-tolerant eucalyptus. The insect L. invasa is a major pest of eucalyptus plantations, and Beauveria bassiana (Bals.) Vuill (Ascomycota: Hypocreales) is being investigated as a potential biocontrol agent against this pest. The fungus B. bassiana can produce metabolites that affect insect biology and survival. Here, we investigated the ability of the entomopathogenic B. bassiana to endophytically develop and induce resistance to L. invasa in a drought-tolerant eucalyptus hybrid. In a greenhouse under semi-controlled conditions, a group of seedlings were sprayed with a solution containing the fungal spores of B. bassiana. The uninoculated seedlings and seedlings inoculated were infested with L. invasa, and their morphometric responses, gas exchange, and chlorophyll indexes were assessed. The number of leaves and height of the inoculated plants was higher than those of the uninoculated plants. The mean CO₂ assimilation rate (A) and transpiration rate (E) were higher for inoculated plants. The inoculated plants showed higher chl a and chl b contents. Compared to the uninoculated plants, the inoculated plants developed much fewer galls, while some showed only scar formations where L. invasa deposited its eggs. These results indicated that inoculating Eucalyptus with B. bassiana promoted resistance to L. invasa. To the best of our knowledge, this is the first study showing that an entomopathogenic fungus can develop endophytically to promote resistance against a galling insect pest.

Eucalyptus cultivation in arid regions is limited by the losses caused by the galling wasp, Leptocybe invasa Fisher and La Salle, 2004 (Hymenoptera: Eulophidae); it oviposits below the epidermis of the central veins, mainly on seedlings in nurseries and/or young plants in the field, causing galls where the insects develop. Galls modify the normal circulation of sap in vascular tissues, ultimately affecting the development of infested plants and resulting in slower growth. Eucalyptus genotypes tolerant to water stress are susceptible to L. invasa, and this pest has no effective control methods. Here, we aimed to (i) determine the initial infestation dynamics of L. invasa in Eucalyptus plants inoculated with Beauveria bassiana and (ii) identify any change in the development of galls. B. bassiana-inoculated seedlings were infested with L. invasa. Susceptible plants were unaffected, and gall development was negatively affected at multiple stages. A fungal solution containing B. bassiana reduced gall development and the emergence of L. invasa adults in eucalyptus plants at considerable rates. The total number of adult emergence holes was 89.74% fewer for inoculated plants when compared to uninoculated plants. These results can help develop B. bassiana products to control L. invasa in susceptible eucalyptus plants for improved, sustainable forestry.

O Estado do Tocantins tem-se destacado nos últimos anos como promissor em reflorestamentos com eucalyptus . Um dos problemas com grande destaque na silvicultura tocantinense é o amplo número de espécies infestantes (conhecidas comumente como rebrotas de Cerrado), resultantes de áreas recém-desmatadas. Objetivou-se com este trabalho avaliar o efeito da deriva simulada do herbicida triclopir e da mistura formulada triclopir + fluroxipir em mudas de clones de eucalipto, ambos em duas doses, correspondentes a 50 e 25% da dose de 7 L ha-1 p.c, recomendados tradicionalmente em pastagem. Foram avaliadas as variações em altura de plantas, variações de diâmetro do caule, relação altura/diâmetro, acúmulo de massa de matéria seca: de folhas, de caules, de ramos, de raízes e total. Os herbicidas afetaram negativamente o crescimento dos clones de eucalipto até os 28 dias após a aplicação. Com base nos resultados, pode-se concluir que o efeito da deriva é menor quando os herbicidas triclopir e fluroxipir + triclopir são aplicados, ambos na dose de 25%, diminuindo, assim, o risco de perdas.

O presente trabalho objetivou avaliar a influência da adubação fosfatada sobre o crescimento e produção do pinhão-manso (Jatropha curcas L.). Mudas de pinhão-manso, com dois meses de idade foram transplantadas no mês de fevereiro de 2007. No mês de junho de 2008 foi realizada poda drástica em todas as plantas na altura de 80 cm do solo. Os tratamentos foram constituídos pelas doses de P2O5: 0, 50, 100, 150 e 200 g cova-1.O delineamento experimental utilizado foi em blocos casualizados,com quatro repetições de oito plantas, totalizando 40 plantas por bloco. O período de avaliação do experimento compreendeu-se entre o mês de outubro de 2008 a outubro de 2009 (correspondente ao 2° ano de avaliação), e entre o mês de outubro de 2009 a outubro de 2010 (correspondente ao 3° ano de avaliação),sendo as variáveis avaliadas:o número de ramos antes da poda, o número de ramos após a poda,o número de ramos com inflorescência,o número de inflorescência planta-1,o número de ramos com cachos,o número de cachos planta-1 e aprodutividade. A poda estimulou o crescimento e produção do pinhão-manso. O incremento na adubação fosfatada elevou a produtividade de pinhão-manso, alcançando uma estabilidade a partir da dose de 150 g ha-1 de P2O5. A cultura de Pinhão-manso pode ser considerada uma espécie que responde à adubação fosfatada.