First Report of Leaf Spot Disease Caused by Exserohilum rostratum on Pineapple in Hainan Province, China

Abstract

Planf Dis. 96:458, 2012; published online as http://dx.doi.org/I0.1094/PDlS-07-ll-0620. Accepted for publicafion 10 December 2011.In June 2011, sympfoms of posfbarvest rot were observed on approximafely 3% of all cherries collected from commercial orchards of culfivars Lapen and Ferrovia in fbe prefectures of Imathia and Pella (northern Greece). Fruif were harvesfed in a timely manner fo avoid overripeness. No wounds or ofher predisposing injuries were observed on the infected fruits. Lesions enlarged rapidly and separated easily from healfhy fissue when pressure was applied. Infecfed fissues were pale and wafer soaked and fhe associafed fungal spores were dark and powdery and easily liberated when mature. The fungus grew rapidly and produced black colonies on acidified pofafo dexfrose agar (2.5 ml of 85% lacfic acid per lifer of nufrienf medium) affer 5 days at 24°C. Identification of fhe pafhogen was based on morphological characferistics (1). Tbe conidial head was radiate, vesicles were nearly spherical and covered with metulae and phialides (biseriafe). Conidia were globose (3 fo 5 pm in diamefer) and usually very rough with irregular ridges, bars, and verrueae. Koch's posfulafes were completed in fhe laborafory by inoculating mature cherry fruifs (cv. Lapen). The fruifs were surface sferilized by dipping in 10% chloride bleach solufion, allowed to dry in a laminar flow hood, and wounded wifh a sharp glass rod fhaf was 2 mm in diamefer. A 40-|al drop of a suspension confaining 20,000 conidia per ml of water was placed on eacb wound. There were 20 inoculated and 20 confrol fruits (similarly wounded and inoculated with a 40-nl drop of sterile disfilled wafer) in a randomized design and incubafed af 24 fo 26°C for 6 days. Koch's posfulafes were satisfied after reisolafing the fungus from inoculafed fruif that developed symptoms similar to those observed on fruif collecfed from orchards. Confrol fruifs did nof show any sympfom of the disease. To our knowledge, this is fbe firsf reporf of the occurrence of Aspergillus niger as the causal agenf of postharvest rots of cherries in Greece. Posfharvest fruif rofs caused by A. niger have been reported in cherry orchards of other countries around the world (2). Because fhis disease causes postharvesf rots of cherry fruits, measures may need to be implemented to manage the pathogen.

Exserohilum rostratum: Characterization of a Cross-Kingdom Pathogen of Plants and Humans

“…Exserohilum species are common molds found in soil and on plants, especially grasses, and they thrive in humid climates. Some species can cause severe plant disease epidemics [31] , [42] . Exserohilum rostratum has been recorded as a minor pathogen of humans, mainly in immunocompromised patients [29] , but proved to be deadly when injected in the epidural space around the spinal column as a contaminant in a corticosteroid fluid [24] .…”

“…Many Exserohilum species are plant pathogens that cause distinct leaf spots and blights. E. rostratum is a plant pathogen that affects a wide range of species, particularly grasses, Poaceae [30] , but also other monocotyledonous plant families [31] . However, under certain circumstances E. rostratum can survive and thrive in human and animal hosts.…”

Supplementary 4

“…Leaf spot diseases of pineapple are always considered less important unless the diseases severely attack the whole plant. Many leaf spot diseases have been reported on pineapple plants such as leaf spot caused by Exserohilum rostratum (Luo et al, 2012) and leaf spot caused by Curvularia clavata (Zhong et al, 2016) found in China. Leaf spot disease can also be caused by Chalara parodoxa as reported by Joy and Sindhu, (2012) in India.…”

Exserohilum rostratum causing sugarcane leaf spot in Iran

“…1b). The fungus was reisolated from leaf Exserohilum rostratum has been reported previously on many monocotyledonous plants (Sivanesan 1987;Leonard et al 1988;Cardona and González 2007;Luo et al 2012), S. officinarum (Zummo 1986) and turfgrass species in Iran (Mirabolfathi and Ershad 2006). To our knowledge, this is the first report of leaf spot caused by E. rostratum on S. officinarum in Iran.…”

“…Pathogenicity tests were conducted on 2-month-old sugarcane plants by spraying a conidial suspension of the fungus (10 5 conidia/ml of water) (Luo et al 2012). The pathogenicity tests were conducted using three replicates for each isolate (Ex 1, Ex 2 and Ex 3), two plants for each replicate and the inoculated plants were held in a greenhouse under ambient conditions (20-25°C, 75-85 % RH).…”