Post-Harvest Control of Palmer Amaranth (Prostko)

I have been getting numerous telephone calls lately regarding the post-harvest (i.e. after field corn) control of Palmer amaranth.  It is extremely important to control this fall population of Palmer plants before they produce more seed which can be added to the soil seed-bank.  A year's worth of good control could go down the drain if these populations are allowed to produce seed! In case you were unaware, I have very specific recommendations for this particular situation on page 62 of the 2012 UGA Pest Control Handbook.  It is critical that growers pay close attention to the size of the Palmer.  If paraquat is applied to weeds larger than 6", control will be poor and this lack of control may even help contribute to the future development of paraquat resistance.  I often suspect that some folks think that I make this stuff up.  However, if you or your growers do not believe me, please refer to Figure 1.  Increasing the paraquat rate and tank-mixtures with 2,4-D or dicamba would help but not enough for me to say that it is a great idea to spray pigweed plants greater than 6" tall.