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Tropentag, October 5 - 7, 2011 in Bonn

"Development on the margin"


Symptoms of Fusarium proliferatum on Maize Leaves

Thi Thanh Xuan Nguyen

University of Bonn, Inst. Crop Sci. and Res. Conserv. (INRES) - Phytomedicine, Germany


Abstract


Maize (Zea mays) is an important food crop and a well-known host of Fusarium species. Some of these including F. proliferatum are capable of producing large quantities of mycotoxins that are harmful to humans. Different Fusarium species have been isolated from maize showing typical rot symptoms at ears or stems. However, no report is available on the symptom development of Fusarium spp. on maize leaves, especially for F. proliferatum producing fumonisin. Maize plants, cultivar Tassilo, were grown under two different light intensities and durations of 5800-6000 lux, 9 hours/day and 18000-20000 lux, 15 hours/day under climate chamber condition. The plants were inoculated by hand spraying the leaves at BBCH 13-15. Data on disease incidence (i.e. the proportion of symptomatic plants within a sampling unit) and re-isolation frequency (i.e. the proportion of the leaf tissues colonized by F. proliferatum) were collected. For microbial initiation, symptomatic and asymptomatic leaves were incubated on CZID media. Disease incidence of F. proliferatum was 40%. Re-isolation frequency from leaves with symptoms was higher than from asymptomatic leaves, with a colonisation frequency of 100% and 63%, respectively. Heavy symptoms of F. proliferatum appeared on young leaves emerging from the whorl from 7 days after inoculation. Holes were present in the emerging leaves or folded leaves were rotten. Mild symptoms including white- or brown- round or oval spots were observed on upper leaves. On old leaves, the symptoms appeared later and less severity with brown or yellow lesion ranging from 0.5 to 2.5cm in length and mostly at the leaf edges. The same symptoms of F. proliferatum were also detected in the green house during winter with low light conditions. This indicates that the symptoms of F. proliferatum appear on maize leaves under less ideal condition of plant growth.


Keywords: Fusarium proliferatum, maize leaves, symptoms


Contact Address: Thi Thanh Xuan Nguyen, University of Bonn, Inst. Crop Sci. and Res. Conserv. (INRES) - Phytomedicine, Nussallee 9, 53115 Bonn, Germany, e-mail: xuan@uni-bonn.de


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