Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

First report of corn kernel brown spot disease caused by Mucor irregularis in China.

Abstract

In October 2012, a brown spot disease was found on maize kernels during a field survey in Nanyang city, Henan, China. The incidences of affected ears and kernels were 2 to 10% (n=600) and 0.08 to 0.4% (n=25 000), respectively. Symptoms first appeared as circular or irregular brown spots on the endosperm. These spots subsequently enlarged or coalesced, resulting in the formation of a large light-brown or light-yellow irregular speckle commonly surrounded by a dark-brown edge. Based on morphological characteristics, molecular investigations (sequence analysis of the rDNA internal transcribed spacer region and D1/D2 region of the nuclear large subunit ribosomal RNA gene) and pathogenicity tests, the causal agent was identified as M. irregularis. This fungus was reported as a pathogen causing human skin diseases in China, America and India, and as a phytopathogen causing fruit rot on durian. This is thought to be the first report of M. irregularis causing maize kernel brown spot disease in China.