Source: Purdue University

The recent wet spell has kept sprayers out of the field and many farmers have reduced their reliance on pre-emergence residual herbicides in corn production in favor of reliance on glyphosate post-emergence. This year is a perfect example of why the industry should not rely totally on post-emergence weed management strategies in corn. It is likely that thousands of bushels of yield potential has been give up as a result across the state because crop yields were not protected from weed competition.

What can you do? About a month ago Purdue University posted an article that showed the crop growth stage restrictions for post-emergence herbicides in corn. Here is another chance to look at this table and see what your options are. Also, keep in mind the weed control efficacy table so you know what herbicides control specific weeds. Also, be realistic and if you have weeds over 1 foot tall, do not expect complete control. All you can really hope for is suppression and lessening the impact on final yield.

Original press release