Incidence of ear rot pathogens under alternating corn tillage practices

The efficacy of periodic plowing in reduced-tillage fields in reducing corn ear rot caused by Stenocarpella maydis, Fusarium moniliforme, F. subglutinans, and F. graminearum was determined over three seasons at Bloekomspruit, South Africa. A positive linear relationship was recorded for Stenocarpella ear rot incidence and surface stubble mass. Moldboard plow plots consistently had lower stubble mass and Stenocarpella ear rot incidence than did reduced tillage practices. A cross-moldboard plow applied after one, two, and three seasons of reduced tillage reduced stubble mass and Stenocarpella ear rot incidence in the respective season only. Stenocarpella ear rot incidence increased during the subsequent season in which the original tillage practices were again applied. Alternating tillage practices would therefore not reduce Stenocarpella ear rot in the long term. Reduced disease incidence can only be achieved by moldboard plowing during each season. Alternating tillage practices had no effect on ear rots caused by Fusarium spp. during all seasons.