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 recor
ded for Stenocarpella ear rot incidence and surface stubble mass. Mold
board plow plots consistently had lower stubble mass and Stenocarpella
ear rot incidence than did reduced tillage practices. A cross-moldboa
rd plow applied after one, two, and three seasons of reduced tillage r
educed stubble mass and Stenocarpella ear rot incidence in the respect
ive season only. Stenocarpella ear rot incidence increased during the
subsequent season in which the original tillage practices were again a
pplied. Alternating tillage practices would therefore not reduce Steno
carpella ear rot in the long term. Reduced disease incidence can only
be achieved by moldboard plowing during each season. Alternating tilla
ge practices had no effect on ear rots caused by Fusarium spp. during
all seasons.