The call of the week has been concerns on the herbicide fomesafen (Flexstar, Reflex). A few farmers believe (and some are correct) that they have Flexstar carryover stunting corn. There is a 10 month wait to plant corn after a Flexstar application just for carryover reasons. If Flexstar is applied after mid-June and is coupled with a dry fall there is a chance for carryover. Corn suffering from Flexstar carryover will display very distinctive leaf symptoms. The corn leaf veins will turn yellow to brown and the midrib will often become distinctly yellowish/brown while the tissue between the veins remain green. This symptomology is sometimes referred to as “tiger striping”. In some cases the corn leaf mid-rib will break over. Experience gained from back 20 years ago when Flexstar was widely used is that corn suffering from Flexstar carryover will show some stunting and leaf discoloration early but often comes out of it with little problem. Judging from that history I would expect much of the same from Flexstar carryover now.
As back in the 1990s, it is easy to confuse corn that is struggling with low temperature/excessive water stress to corn suffering from Flexstar carryover. Many corn hybrids under a cold wet environment will display tiger striping leaf symptoms with a subtle difference from Flexstar injury. The leaf striping will be yellow between the veins with the veins remaining green, which is just the opposite of what is seen with Flexstar carryover. Regardless of whether the corn is suffering from Flexstar or cold wet conditions, the solution to the problem is warm, sunny weather.
Many cotton growers last week saw the forecast that called for rain over the weekend and applied Reflex. The rain with respect to the Reflex application was very timely and worked it into the soil. Based on all our research as well as research performed by my colleagues in the Mid-South, once Reflex is worked into the soil with rainfall it will not cause cotton injury. The only injury Reflex will cause is if it is not worked into the soil with rain prior to cotton emergence and an ill-timed rainfall event splashes Reflex up onto the newly emerged seedlings. However, for many growers this is the first time they have used Reflex under the direction of the new 24c label and a few are wondering if the reason the cotton looks poorly right now is due to the Reflex. I have looked at a number of plants from these fields as well as walked a couple fields. In every case the reason the cotton looks poor is due to the cold weather. This was reflected in research we are conducting at Milan where in cotton planted last Monday we applied Reflex pre emergence at various rates as well as tank-mixtures of Reflex plus Cotoran and Reflex plus Caparol at various rates. Though the cotton was cracking over the weekend during the rain event, the cotton treated with Reflex or a Reflex tank-mixture showed no more injury than the cotton that received no pre emergence herbicide.
