Sônia Maria Alves de Oliveira

Doenças fúngicas pós-colheita em mamões e laranjas comercializados na Central de Abastecimento do Recife

Fungal diseases constitute one of the main causes of losses during commercialization of tropical fruits. Papaya (Carica papaya) and orange (Citrus spp.) fruits were analyzed in relation to the disease incidence and frequency of the pathogenic species for six months, in the Distribution Centre of the city of Recife, Pernambuco, Brazil. Forty fruits of each species were evaluated monthly at five commercialization points, for a total of 200 fruits/month/species. A great diversity of diseases occurred in papaya fruits, where incidences ranged from 39,71% to 0,07%, with the higher level for stem-end rot. In orange fruits the disease incidence was 11,85% and 0,87%, for Lasiodiplodia stem-end rot and antracnose, respectively. The pathogens that presented higher frequencies were Colletotrichum gloeosporioides (44,95%) in papaya and Lasiodiplodia theobromae (11,85%) in orange. The diversity of diseases verified in this study suggests a need for more effective control measures during the production and postharvest phases of papaya and orange, seeking to propitiate reduction of the losses.

Caracterização enzimática e patogenicidade cruzada de Colletotrichum spp. associados a doenças de pós-colheita

Anthracnose caused by Colletotrichum spp. may result in great losses in field productions and post-harvest conditions for several cultures and their products. The objective of this work was to test the pathogenicity of C. gloeosporioides isolates from cashew (Anacardium occidentale) (CAJ), mango (Mangifera indica) (MG), papaya (Carica papaya) (MM) and passion fruit (Passiflora edulis) (MR) and C. musae from banana (Musa spp.) (BAJ); to evaluate the production of extra cellular hydrolytic enzymes (amylolytic, celullolytic, lypolytic, proteolytic) by the isolates on specific solid culture media; and to detect electrophoretic patterns of total proteins and isoenzymes (a-esterase, b-esterase, acidic phosphatase and leucine aminopeptidase). In crossed pathogenicity tests, all Colletotrichum spp. isolates produced necrotic and depressed lesions on fruits, except on passion fruit, which was susceptible only to the MR isolate. The isolates of C. gloeosporioides produced amylolytic, lypolytic, proteolytic, and celullolytic enzymes, and C. musae did not produce any detectable celulase. Electrophoretic analysis of total proteins and isoenzymes showed variations in the number and position of the bands among all isolates in the systems used, except for leucine aminopeptidase, which was monomorphic.

Efeito da temperatura e período de molhamento sobre o desenvolvimento de lesões de Colletotrichum musae em banana

The banana is the second more consumed fruit in the world, but there is a product loss of about 40% from field to consuming market due to several factors including the postharvest diseases, being the anthracnose most significative among them. Considering the necessity of studying the environmental factors that affect this losses, the objective of this work was to evaluate methods of inoculation (PDA discs with pathogen structures and suspension of conidia with and without wound) and the influence of temperature (10, 15, 20, 25 and 30oC) and wet period (0, 12, 24 and 36 hours) on the development of Colletotrichum musae on banana. The fruits were inoculated with 17 isolated of C. musae and all of them showed pathogenicty when inoculated with wound independently of the type of inoculum used. In the trial envolving temperature and wet period three isolates of C. musae: MAG2, SFV1 and FSA were used, which showed high, intermediate and low aggressiveness, respectively. The temperatures around 20, 25 and 30oC and all wet periods tested favored the lesion development, being observed the biggest lesions under temperatures of about 25 and 30oC, as well as lesion reduction induced by all isolates with decreasing of temperature. The temperature around 15oC favored the lowest disease development on banana fruit.

Controle alternativo da podridão peduncular em manga

The aim of this study was to evaluate the effect of alternative products in mango sleeves inoculated challenged with Lasiodiplodia theobromae and its influence on the mycelial growth of the pathogen in vitro. Mangoes were treated with: potassium phosphate (50, 100 and 150), hidroxidobenzoico acid (5, 10 and 15), calcium chloride (0.13, 0.26 and 0.39) (in mmol), ultraviolet light ( 10, 20 and 30 min.), extracts of garlic, melons of the Caetano, bark of mango (25, 50 and 75%) and water (control). The design was a split plot. 106 con./mL was inoculated immediately after each treatment (T1), twelve hours after (T2) and twenty-four hours after (T3). In T1, the best treatments were PO (50 mmol) and CC (0.13 mmol). T2 in there were CC (0.13 mmol), AH (5 mmol), EA (25%) and FP (100 mmol). In T3 there was no difference between treatments. In vitro treatments were mixed into the culture medium. After solidification it was placed in the center of each plate, structures of the phythopathogen. The model was in DIC with 6 replications. After 48 hours it was measured the diameter of the colony. The best treatments were FP (100 and 150 mmol), ECM (50 and 75%) and EA (50%).

Efeito do estádio de maturação, tipo de inóculo e local de inoculação na severidade da podridão peduncular em manga

The mango crop is one of the principal activities of Brazilian agribusiness, and it has grown steadily over recent years. Postharvest rots are responsible for great losses in fruit storage, with prominence to steam-end rot, caused by Lasiodiplodia theobromae and Fusicoccum parvum. The objective of this work was to compare isolates of the species L. theobromae and F. parvum on the aggressivity, inoculum type, inoculation place and state of ripeness in cv. Tommy Atkins. The aggressivity test was carried out with five isolates of L. theobromae and 10 isolates of F. parvum. Isolates L2 and L5 of L. theobromae and isolates F6 and F10 belonging to the species F. parvum were considered the most aggressive. These isolates were tested in relation to the state of ripeness (2; 2,5; 3; 4 and 5), inoculum type (disc of PDA containing structures of the plant pathogens and conidia suspension - 105 conidium/mL) and inoculation place (peduncle region and equatorial area) on the mango. In general, the more mature the fruit, the greater the severity of the disease for isolates of the two plant pathogens, independent of the place of inoculation and the type of inoculum. In the earliest states of ripeness the smallest lesions were observed when inoculated with conidium suspension. As for the inoculation place, no marked influence was observed for the isolates of the plant pathogens studied

Escala diagramática para avaliação da severidade da antracnose em bastão do imperador

A antracnose, causada pelo fungo Colletotrichum gloeosporioides (Penz.) Sacc., e uma importante doenca do bastao do imperador [Etlingera elatior (Jack) Smith] no Nordeste brasileiro. Considerando a inexistencia de metodos padronizados para quantificacao dessa doenca, foi elaborada uma escala diagramatica com os niveis 1, 2, 4, 8, 16, 32, 64, 82 e 92% de area da bractea lesionada, testando-se a acuracia, a precisao e a reprodutibilidade das estimativas de severidade da antracnose com e sem a utilizacao da escala. A escala diagramatica foi validada por 10 avaliadores, usando 45 bracteas com diferentes niveis de severidade da antracnose. Sem a escala, a maioria dos avaliadores superestimou a severidade da doenca. Com a escala, os avaliadores obtiveram melhores niveis de acuracia e precisao, com os erros absolutos concentrando-se na faixa de 10%. Os avaliadores apresentaram elevada repetibilidade (95%) e reprodutibilidade (³90% em 75,6% dos casos) das estimativas com a utilizacao da escala. A escala diagramatica proposta demonstrou ser adequada para avaliacao da severidade da antracnose em bastao do imperador.

Avaliação de indutores de resistência em algodoeiro a murcha de fusário: atividade enzimática e índice de infecção

Os indutores de resistencia acibenzolar-S-metil, metil jasmonato e fosfato de potassio (K2HPO4), nas concentracoes de 0,2 g/L, 0,1 mL/L e 0,1 M, respectivamente, foram testados em plântulas de algodoeiro (cv. BRS Cedro), para o controle de Fusarium oxysporum f. sp. vasinfectum. Foram realizadas uma e duas aplicacoes com todos os indutores em plântulas com e sem inoculacao do fitopatogeno. Constatou-se que o menor indice de infeccao foi obtido com o uso do metil jasmonato aplicado duas vezes. Amostras de folhas e caule foram avaliadas quantitativamente para as enzimas β-1,3-glucanase, peroxidase e quitinase. As plantas testemunhas sem inoculacao apresentaram as maiores atividades das enzimas peroxidase e β-1,3-glucanase no caule. Nas folhas das plantas que receberam os tratamentos com metil jasmonato (uma aplicacao com inoculacao), a atividade das enzimas peroxidase e quitinase foram as maiores. Nas amostras de caule nao houve atividade detectada da enzima quitinase.

Proteção a murcha de fusário do tomateiro com Acibenzolar-S-Metil e Ácido beta-Aminobutírico, em campo

Os elicitores abioticos sao compostos que induzem a sintese de fitoalexinas, como tambem outras respostas de defesa da planta. Visando a obtencao de uma alternativa de controle para murcha de fusario do tomateiro (Lycopersicon esculentum) foram avaliados os indutores Acibenzolar-S-Metil (ASM) e Acido b-Aminobutirico (BABA), em diferentes doses e epocas de aplicacao via foliar. Foram utilizadas as cultivares Viradoro e IPA-6, suscetiveis a raca 1 de Fusarium oxysporum f.sp. lycopersici. A avaliacao de sintomas externos foi realizada semanalmente e a avaliacao final realizada aos 43 dias apos a inoculacao das plantas, atraves da analise de sintomas externo e interno, utilizando-se duas escalas de notas. Apenas na cv. IPA-6 houve reducao no indice de doenca no tratamento com BABA na maior dose, aplicado cinco dias antes da inoculacao.

Influência da temperatura, umidade, concentração de inóculo de Acidovorax avenae subsp. citrulli e idade do fruto no desenvolvimento da mancha-aquosa em melão

The influence of temperature (15, 20, 25, 30, 35 and 40 °C), humidity (0 and 6 h in a moist chamber), inoculum concentration of Acidovorax avenae subsp. citrulli (0; 3.4 x 101; 3.4 x 102; 3.4 x 103; 3.4 x 104; 3.4 x 105; 3.4 x 106 and 3.4 x 107 CFU.ml-1) and fruit age (40, 50, 60 and 70 days) on the severity of fruit blotch of melon (Cucumis melo) yellow type was studied. Fruits were inoculated by sub-epidermal injection and incubation period, external lesion diameter and lesion depth were determined . The incubation period was not significantly affected by temperature in fruits kept within or without a moist chamber. Larger external lesions were observed on fruits kept at 30 °C (19.5 mm) in a moist chamber for 6 h and 35 °C (15.3 mm) without a moist chamber. Deeper lesions were observed on fruits kept in a moist chamber at 30 °C (17.5 mm). Under dry conditions, deeper lesions were observed at 25 °C (11.7 mm) and 30 °C (11.3 mm). No disease symptoms were observed on fruits kept at 15 and 20 °C. The humidity did not influence the lesion diameter and depth at 35 and 25 °C, respectively. Lesion diameter and depth were positively correlated to inoculum concentration. Fruit age did not significantly influence lesion diameter, 50-day old fruits showed deeper lesions.

Low doses of gamma radiation in the management of postharvest Lasiodiplodia theobromae in mangos

The postharvest life of mango is limited by the development of pathogens, especially fungi that cause rot, among which stands out the Lasiodiplodia theobromae. Several control methods have been employed to minimize the damages caused by this fungus, chemical control can leave residues to man and nature; physical control by the use of gamma radiation in combination with modified atmosphere and cold storage. The use of gamma radiation helps to reduce the severity of the pathogen assist in the ripening process of fruits, even at low doses (0.25, 0.35 and 0.45 kGy) chemical properties such as pH, soluble solids, acid ascorbic, titratable acidity and also the quality parameters of the pulp showed no damage that are ideal for trade and consumption of mangoes. This treatment can be extended for use in the management of diseases such as natural infections for penducular rot complex that has as one of L. theobroma pathogens involved.