Tropical Plant Research

Tropical Plant Research

An Internationl Journal by Society for Tropical Plant Research

E-ISSN: 2349-1183 P-ISSN: 2349-9265
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2017, VOLUME 4 ISSUE 1Pages: 109-114

Colonization of stem borer damaged maize plants by aflatoxigenic Aspergillus species in Zimbabwe

N. Nleya*, Y. O. Nyararai, M. Mawanza and F. N. Mlalazi
*National University of Science and Technology, Department of Applied Biology and Biochemistry, Box AC 939, Ascot, Bulawayo, Zimbabwe
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Abstract:
The worldwide contamination of food and feed with mycotoxins is a significant problem. Aflatoxins are major mycotoxins of agro-economic importance produced by some Aspergillus species. Aflatoxigenic Aspergillus species were isolated from insect larvae damaged maize stalks and characterized. The fungi were isolated from the stems, ears and silks of the plant. Aflatoxin production by the isolates was determined using the ammonium hydroxide method as well as the ultra violet fluorescence method. The Lepidopteran species feeding on the crop was identified as Busseola fusca. The Aspergillus species isolated were identified as Aspergillus flavus and Aspergillus parasiticus. This was done using macro- and microscopic features. A total of 35 isolates were obtained of which only 17 were aflatoxigenic. From the aflatoxigenic species 88% were A. parasiticus whilst 12% were A. flavus. Insects were however negative for aflatoxigenic fungi implying that these insects do not act as direct vectors of aflatoxigenic fungi, but however predispose the crop to fungal infection by damaging the physical barrier.
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