Volume 4 - 2014 - Issue 1


1. Post-harvest treatments for controlling crown rot disease of Williams banana fruits (Musa acuminata L.) in Egypt

Authors: Abd-Alla MA, El-Gamal NG, El-Mougy NS, Abdel-Kader MM

Recieved: 09 November 2013, Accepted: 27 December 2014, Published: 11 February 2014

Fusarium semitectum was isolated at high frequency from collected banana cultivar "Williams" showing crown rot symptoms from commercial markets. The inhibitory effect in vitro of tested essential oils on mycelium growth was higher than on conidium germination of F. semitectum. Complete inhibition of fungal growth and spore germination was recorded at the concentration of 1.0% of tested cinnamon and bitter almond oils. Under storage conditions, artificially inoculated bananas showed reduction in both crown rot disease incidence and severity when treated with cinnamon, thyme bitter and sweet almond oils. Complete reduction (100.0%) of crown rot disease incidence of banana fruits was recorded at the concentration of 4.0% of applied cinnamon and thyme oils, followed by sweet almond and bitter almond oils which they reduced disease incidence by 87.1 and 78.7%, respectively. Stored bananas treated with cinnamon, bitter and sweet almond oils showed no significant differences compared to the control with respect to odour, flavour, taste and overall acceptability. Hence cinnamon, thyme, bitter and sweet almond oils treatment developed during the current study without affecting the organoleptic properties recommended as a safe and cost-effective commercial method for treating bananas to control crown rot disease.

Keywords: Colletotricum musae – fungal growth reduction – plant oils – stored fruits

 

2. Powdery mildew of Celtis australis: a report from Himachal Pradesh, India

Authors: Gautam AK

Recieved: 18 December 2013, Accepted: 08 January 2014, Published: 11 February 2014

A detailed study of a powdery mildew observed on Celtis australis leaves was carried out in the present study. The symptoms appeared as white mycelia on leaves with embedded small black to brown spherical ascomata. Morphological and microscopic analyses of diseased samples revealed that this fungus belongs to Erysiphe section Uncinula. Further investigation identified it as Erysiphekusanoi which is new to Himachal Pradesh. A description and an illustration of the specimen are given.

Keywords: circinate appendages – Erysiphe kusanoi – mediterranean hackberry – new record

 

3. Plant associated fungi from Nauru, South Pacific

Authors: McKenzie EHC

Recieved: 17 January 2014, Accepted: 11 February 2014, Published: 22 February 2014

Eighteen fungal taxa were collected in Nauru in 1980. They comprised four rust fungi, one smut fungus, several species that cause leaf spots and some saprobes. This is the first report of any plant associated fungi from Nauru.

Keywords: first records – oceania – plant pathogens – saprobes

 

4. Pathological response and biochemical changes in Allium cepa L. (bulb onions) infected with anthracnose-twister disease

Authors: Alberto RT

Recieved: 10 January 2014, Accepted: 20 February 2014, Published: 16 March 2014

Development of novel ways to address the losses and decreased production of onion in the Philippines due to diseases, has been of great interest since 1996. To achieve this, basic knowledge on the pathogenesis and host response are crucial in developing resistant varieties. Results generated from the pathogenicity test confirmed Colletotrichum gloeosporioides and Gibberella moniliformis are both pathogenic to the three onion cultivars tested (Yellow Granex, Red Creole and Shallot). Disease incidence and disease index were highest in Yellow Granex, followed by Shallot and Red Creole. Application of GA3 at 100 and 1000 µg/ml in the neck of onion plants produced severe twisting and elongation and microscopic examination showed that the cells are exceptionally long and wide as compared to the cells of the uninoculated plants. Biochemical analysis unveiled that protein content, amount of reducing and total sugars as well as phenols were low in all of the infected plants as compared to the uninoculated plants. A trend that shows a correlation between decreasing protein, sugar and phenols content and decreased resistance.

Keywords: anthracnose-twister disease – Colletotrichum gloeosporioides – Gibberella moniliformis – Gibberellic acid

 

5. Fusarium Wilt of Chrysanthemum – Problems and Prospects

Authors: Singh PK, Kumar V

Recieved: 01 February 2014, Accepted: 04 March 2014, Published: 17 March 2014

Chrysanthemum flower production is adversely affected by many bacterial, fungal and viral diseases. Wilt caused by Fusarium oxysporum f. sp. chrysanthemi is one of the most serious diseases and causes severe yield losses. The pathogen enters the plant, multiply and blocks the vascular system with or without involvement of toxins and enzymes. Multiplication medium, pH and temperature plays significant role on the growth and sporulation of Fusarium oxysporum. Moderate temperatures, high humidity, availability of plant nutrients in soil encourage rapid disease development. High inoculum density causes greater disease incidence, hasty disease advancement and low flower yield. Degree of symptom development is related with the cultivar resistance and susceptibility. Plant extracts, polar and non-polar fractions, their pure compounds, and essential oils have potential antimicrobial activity against Fusarium oxysporum. The active phyto-constituents responsible for antifungal properties are low molecular weight phenols, tannins and lignin. Trichoderma and other phyto-pathogenic fungi are known to diminish wilt disease caused by Fusarium oxysporum f. sp. chrysanthemi. Myco-parasitism, antibiosis, nutrient competition and starvation, siderophore production and induction of systemic resistance are the major mechanism employed by Trichoderma for controlling pathogens. The present paper is intended to discuss the aspects of epidemiology, pathogenesis and biological control measures of Fusarium oxysporum with emphasis on Chrysanthemum wilt.

Keywords: botanicals – Chrysanthemum – Fusarium oxysporum – Trichoderma

 

6. Redisposition of species from the Guignardia sexual state of Phyllosticta

Authors: Wulandari NF, Bhat DJ and To-anun C.

Recieved: 11 October 2013, Accepted: 11 November 2013, Published: 30 June 2014

Several species named in the genus “Guignardia” have been transferred to other genera before the commencement of this study. Two families and genera to which species are transferred are Botryosphaeriaceae (Botryosphaeria, Vestergrenia, Neodeightonia) and Hyphonectriaceae (Hyponectria). In this paper, new combinations reported include Botryosphaeriacocöes (Petch) Wulandari, comb. nov., Vestergrenia atropurpurea (Chardón) Wulandari, comb. nov., V. dinochloae (Rehm) Wulandari, comb. nov., V. tetrazygiae (Stevens) Wulandari, comb. nov., while six taxa are synonymized with known species of Phyllosticta, viz. Phyllosticta effusa (Rehm) Sacc.[(= Botryosphaeria obtusae (Schw.) Shoemaker], Phyllosticta sophorae Kantshaveli [= Botryosphaeria ribis Grossenbacher & Duggar], Phyllosticta haydenii (Berk. & M.A. Kurtis) Arx & E. Müller [= Botryosphaeria zeae (Stout) von Arx & E. Müller], Phyllosticta justiciae F. Stevens[= Vestergrenia justiciae (F. Stevens) Petr.], Phyllosticta manokwaria K.D. Hyde [= Neodeightonia palmicola J.K Liu, R. Phookamsak & K. D. Hyde] and Phyllosticta rhamnii Reusser[= Hyponectria cf. buxi (DC) Sacc.]. In this paper, identification of “Guignardia” species is based on morphological characteristics. A large number of taxa labeled as “Guignardia” in literature, could not be loaned from various herbaria, or are lost or untraceable are listed as ‘doubtful species’ in view of insufficient supportive taxonomic data. Fresh collections, cultures and molecular sequence data are needed to clarify the phylogeny and taxonomy of cryptic species.

Keywords: Dothideomycetes - Guignardia – plant diseases – saprobes – taxonomy

 

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Plant Pathology & Quarantine Online publishes reviews, research articles, methodology papers, and taxonomic works in the field of plant pathology. The official journal language is English.

 

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