A low level of southern rust was detected earlier this week in Craighead, Lee, Jefferson, Phillips, and Woodruff counties bringing the total county count to eight (Fig. 1). The highest disease severity was similar to that reported earlier this week with 50 to 100 pustules per plant on a few plants in a single area of the field. So, continue to watch late planted corn closely for southern rust development, which will likely increase over the next two weeks. See earlier reports for management recommendations.
Northern corn leaf blight has been easier to find on susceptible hybrids and may be of concern on those high risk fields. Southern corn leaf blight (Fig. 2) has been detected in the central part of the state (Prairie Co.) with a low to moderate level of disease on susceptible hybrids in some fields. Ear rots being reported include diplodia ear rot and trichoderma ear rot. Also, in the central and northern counties, banded sheath blight, which is caused by the same pathogen that causes sheath blight of rice and aerial blight of soybean has been observed, but no fungicides are recommended for this disease. Firstly, it is located too low in the canopy for good fungicide contact and secondly, it is not a major disease of corn.