Isolation and molecular detection of cephalosporium acremonium: the causative agent of black bundle disease in maize

Several diseases affect maize plants and one among them is black bundle disease, causal organism of which is yet to be confirmed with conflicting reports appearing in literature. In the present work, an effort was made to record the disease incidence by carry out filed surveys in Southern most district of Karnataka state, India and also to isolate and identify the causal organism. The surface sterilized pith tissue from the infected plants was cultured on PDA medium to identify the organism in the affected vascular tissue. The isolated tissue produce Cephalosporium acremonium which was confirmed based on morphological characters. In addition, Simplicillium sp. and Macrophomina phaseolina were also isolated from the same infected plant material and suspected to have participated in the disease development. In accordance with several reports in literature, Cephalosporium acremonium was tested and confirmed as the causal organism of disease in green house experiments by following the Koch’s postulates. This is in contrast with some earlier reports, wherein the exact symptoms of black bundle disease were reported as barren stalks in corn caused by Fusarium sp. The simplicillium sp. which had morphological similarity with C. acremonium and had an ambiguous taxonomic status in literature was confirmed as a distinct species through PCR based diagnosis.