Photo: It is impossible to tell by looking at frost-damaged sorghum-sudangrass what the prussic acid levels may be. Silage Corn In fields where rootworm Bt hybrids have been used for three or more consecutive years, resistance among corn rootworm populations is suspected. Producers can no longer rely solely on Bt rootworm hybrids for protection against rootworm injury. See the 2020 Canadian…
