As expected carryover injury from fomesafen (Flexstar, Prefix, Reflex, Intimidator, Marvel, Dawn, Rhythm, etc.) is starting to show in some fields. The reason it is showing now is due to all the rain allowing any herbicide carryover to more completely get into the soil solution.
Fomesafen carryover injury in corn and grain sorghum looks similar. Expect to see stunting and interveinal chlorosis as pictures below sent from crop consultants this week clearly show.
In some cases the injury is more substantial with some leaves showing burn. This burning will be particularly apparent in grain sorghum as it is 4 times more susceptible to fomesafen carryover than corn.
There have been just a hand full of reports, but more folks may see symptoms as they evaluate their fields over the next week or so. The last time we had a significant number of fomesafen carryover reports was back in 2012. That scenario was different then than now with a relatively later planted corn crop this year compared to the spring of 2012. However the set up was similar with later planting of soybeans in the previous year. Pigweed was the target then as well with a lot of Flexstar being applied in late June and July. The fall in 2014, like in 2012, was dry and cool which helps make the fomesafen more persistent.
Fortunately, most of the corn suffering from fomesafen carryover in 2012 shook it off after about 10 days and went on to make a good crop. I would expect a similar outcome this spring with corn that is showing the stunted/yellowing symptoms now.
The grain sorghum may very well be a different story. Grain sorghum fields with fomesafen carryover will emerge fine but once they get into the light they may “go backwards”. With grain sorghum it can be hard to tell what the cause is as grain sorghum seedlings have an a sundry of issues that will make them go backwards like atrazine injury, greenbug injury, etc. but if the veins show the “striping” as seen above fomesafen was likely at least part of the problem.