One of the main diseases occurring in clonal nurseries of Eucalyptus spp. is powdery mildew caused by the fungus Oidium eucalypti. This work evaluated the efficiency of biological products based on Trichoderma spp. and Bacillus spp. applied as preventive and curative treatments for the control of Oidium eucalypti in clonal seedlings of E. benthamii Maiden et Cambage. Treatments were: Trichoderma harzianum (THP), T. atroviride (TAI), T. harzianum (THE), Trichoderma spp. (TTA), Bacillus spp. (BNE), Sulfur (KUM), Difenoconazol (SCO) and distilled water (AD). Treatments were applied preventively by spraying seven days before inoculation of the pathogen, and in curatively, ten days after inoculation. Weekly evaluations of the incidence and severity of the disease were done. The analyzed variables were: Disease Index (ID) and Incidence (I), calculating the area under the disease curve (AUDPC) for each treatment. The results pointed BNE (Bacillus spp.) and TAI (isolate T. atroviride) as effective preventive treatments and BNE (Bacillus spp.), applied curatively for the control of O. eucalypti in E. benthamii seedlings, proving that treatments based on biological products may be effective for controlling eucalyptus powdery mildew in clonal nurseries.
The objective of this work was to evaluate the effect of the collection period and of the exogenous application of indolebutyric acid (IBA) on the rooting of cuttings from adult pecan (Carya illinoinensis) plants. The experiment was carried out in a greenhouse with intermittent mist irrigation, from December 2017 to October 2018. The experimental design was completely randomized, in a 4x5 factorial arrangement, with four collection periods (spring, summer, autumn, and winter) and five concentrations of IBA (0, 2,000, 4,000, 6,000, and 8,000 mg L-1). For the cuttings collected during summer and autumn, there was a linear relationship between rooting and the increase of the IBA concentration. The best results for rooting, callus formation, mean number of roots, mean root length, and root dry and fresh mass are obtained for the cuttings collected during summer, with the application of 8,000 mg L-1 IBA on the base of each cutting, under a mist irrigation system. The rooting of cuttings from adult pecan plants with the application of IBA is possible, being an alternative propagation method for the species.
O objetivo do presente trabalho foi avaliar o efeito da luminosidade e temperatura na germinação de sementes de Carya illinoinensis (Wangenh) K. Koch. Para uniformizar o processo de embebição, as sementes foram previamente submetidas ao processo de escarificação mecânica. O delineamento experimental foi inteiramente casualizado, arranjado com esquema fatorial 3x4, no qual foram testados três regimes de luminosidade (ausência de luz, luz contínua e luz alternada de 12 horas) e quatro condições de temperatura (20°C, 25°C, 30°C e alternada de 12 horas a 15°C e 12 horas a 25°C), com cinco repetições. Variáveis avaliadas foram emissão de radícula (%), o índice de velocidade de germinação (IVG), o tempo médio de germinação (TMG), as plântulas normais (%), as plântulas anormais (%), as sementes duras (%), as sementes mortas (%), o comprimento de raiz e da parte aérea (mm/plântula). A combinação de ausência de luz e temperatura elevada favorece a emissão da radícula e o IVG, e reduz TMG, assim como proporciona maior comprimento de raízes e parte aérea. Entretanto, a temperatura de 25°C em conjunto com ausência de luz obteve resultado superior para formação de plântulas normais, sendo essa combinação mais indicada para a germinação de sementes de C. illinoinensis.
Seed analysis tests should be performed under standard conditions for each species, so that the results can be reproducible anywhere. Seeds of the forest species Toona ciliata var. australis have been commercialized in Brazil despite no standard conditions for their analysis have been published. The objective was to determine basic information about temperature and photoperiod for the germination test and the imbibition time and volume of water for electrical conductivity. In the germination test the seeds were incubated at 15, 20, 25 and 30 °C with 0, 12 and 16 h of light. The electrical conductivity was evaluated up to 108 h after immersion of the seeds in 50 and 100 mL of deionized water. The conditions of 25 °C and 16 h of light provided higher amount of normal seedlings. At 15 °C all seeds remained hard regardless the photoperiod used, however, it became absent when light was added at higher temperatures. The electrical conductivity test should be performed with a volume of 50 mL and evaluated after 24 h of imbibition. It also showed a stronger correlation between normal seedlings, being a promising vigor evaluation test for this species.
Mini-cutting technique of tree species is an effective method of maintaining desirable features of plant matrices and uniformity. The objective of the present research was to determine substrate and concentration of indolebutyric acid (IBA) more suitable for mini-cuttings of Carya illinoinensis rooting. The experiment was carried out in a greenhouse with mist, from February to May 2018. The used experimental design was in blocks with a factorial arrangement of 3 x 5, in which three substrates were tested: carbonized rice husk, vermiculite and perlit; and five IBA concentration : 0, 2,000, 4,000, 6,000 and 8,000 mg L-1. The mini-cuttings were apical, produced from seedlings, with eight months of age. Mini-cuttings were made with two leaves cut in half and 8 to 10 cm in length. The use of IBA influenced results obtained with all substrates, except for the variable number of roots, in which only IBA effect was observed. However, higher results were obtained with IBA uses together with substrate carbonized rice husk, obtaining estimated maximum point of 91% of rooted mini-cuttings with 3,957 mg L-1 IBA concentration. For other evaluated variables, except root numbers, it was also observed superior results close to 4,000 mg L-1 IBA concentration with substrate carbonized rice husk. Results indicate the possibility of Carya illinoinensis propagation by mini-cutting technique and as an alternative for this specie plantlets production.
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