Mônica Danielly de Mello Oliveira

Avaliação da atividade de indutores de resistência abiótica, fungicida químico e extratos vegetais no controle da podridão-negra em Abacaxi 'Pérola'

Black rot of pineapple, caused by Chalara paradoxa (De Seyn.) Sacc., is a postharvest disease responsible by high losses on fruits destined to the fresh market and to the processing industry. Penetration of fungus inside cells occurs through wounds and stem cutting, causing infection. The objective of this work was to evaluate the effect of abiotic resistance inducers, chemical fungicide and natural plant extracts on black rot of pineapple control. 32 fruits of pineapple cv perola were used. They were disinfested with sodium hypochlorite (commercial product) at 4% for 5 minutes. After drying at room temperature, fruits were treated, by spraying, with: 1) Distilled water (control), 2) Derosal 3) Bion® (Acibenzolar-S-methyl); 4) Ecolife®; 5) Agro-Mos®; 6) Allium sativum extract at 20%; 7) A. cepa at 20% and 8) Azadirachta indica at 20%. Treated fruits were incubated on humid chamber with polyethylene bags during 24 hours before inoculation procedure using a mycelia disk added to a wound at the epidermic area of the fruit. Evaluation of disease progress was done by a disease index: 1- no symptoms, 2- black rot on epidermis reaching 1-5 simple fruits, 3- black rot on epidermis reaching 6-10 simple fruits, 4- internal brown yellow rot, 5- black rot and disintegration of internal area in more than 50%. The experimental design was a completely randomized with eight treatments and five replicates, using general linear models with multinomial distribution and the averages were compared by Scott-Knott test at 5%. The best results were found in the Ecolife treatment with longer fruit life span and less severity in the symptoms of the disease.

Inoculação de Curvularia eragrostidis em inhame (Dioscorea alata) cv. São Tomé

Objetivou-se selecionar o método de inoculação de Curvularia eragrostidis em mudas de inhame (Dioscorea alata) cv. São Tomé para a determinação da infecção e do período de latência. O isolado de C. eragrostidis foi obtido a partir de folhas de inhame com sintomas da doença. Plantas com 45 dias de idade, cultivadas em casa de vegetação, foram inoculadas com o patógeno da seguinte forma: T1 – Suspensão de esporos (1x10 conídios mL); T2 Discos de colônia de 10 mm fixados com fita adesiva (dois na face abaxial e um na face adaxial); Leite, R.P.; Nascimento, L.C.; Oliveira, M.D.M. Inoculação de Curvularia eragrostidis em inhame (Dioscorea alata) cv. São Tomé. Summa Phytopathologica, v.44, n.3, p.281-282, 2018.

Genetic diversity of Fusarium spp. in pineapple ‘Pérola’ cultivar

This study aimed to determine the genetic variability of isolates of rotting of pineapple fruitlet core in Brazil on the states of Paraiba, Pernambuco and Rio Grande do Norte, based on phylogenetic analysis of the RPB2 gene, morphocultural markers and aggressiveness of the isolates. The phylogenetic reconstruction of maximum parsimony and bayesian inference of the isolates were performed. Twenty-seven phylogenetic lineages were characterized with morphocultural markers on potato dextrose agar and synthetic nutrient-poor agar. The aggressiveness of these lineages were characterized in leaves and fruits of pineapple ‘Pérola’ cultivar. The Phylogenetic reconstruction showed close relationship between isolates of this study and phylogenetic lineages of F. guttiforme, F. ananatum and F. oxysporum by analysis of RPB2 gene. Phylogenetic lineages of this study shared significant morphocultural markers similar to those described for this species. Overall, the lineages related with Fusarium oxysporum Species Complex were more aggressive to the fruits of the Fusarium lineages related with Fusarium fujikuroi Species Complex. It is possible that F. ananatum and F. guttiforme or other lineages closely related to these species or F. oxysporum are present in the fields causing pineapple rotting fruitlet core in fruits of pineapple ‘Pérola’ in Brazil. The used markers determined high genetic variability in isolates analyzed in leaves and pineapple fruit ‘Pérola’ in the states of Paraíba, Pernambuco and Rio Grande do Norte of Brazil and the pathogenic lineages analyzed were better adapted to the fruits than to the detached leaves in pineapple ‘Pérola’ analyzed.

Indicadores de estresse salino em abacaxizeiro cultivado na ausência e presença de fitorreguladores

To assess the effects of salt on the pineapple MD Gold during the multiplication and rooting phases in vitro, this study evaluated its performance in different concentrations of NaCl in the absence or presence of growth regulators. Pineapple shoots were inoculated on MS solution in the absence and presence of the growth regulators naphtaleneacetic acid (NAA) and 6-benzlaminopurine (BAP) and different concentrations of NaCl (Control - 0, 50, 100 and 150 mM). Monthly, shoots were subcultured and it was analyzed height, number of alive and dead leaves, rates of sprouting and rooting. During the multiplication in the absence of NAA and BAP, the NaCl treatments caused significant reduction in growth and development of pineapple shootings, expressed by the height and number of leaves, the highest dose, which was not observed in the presence of growth regulators. Occurring during the first 60 days, an increase in leaf production. However, after 90 days, there was a decrease in average living leaves in the shoots treated with salt. The in vitro cultivation of pineapple in the presence of salt is more efficient in the presence of NAA and BAP, ensuring continued growth, increasing the number of leaves, producing new buds and accelerating the process of rooting.