Texas panicum can be difficult to control in peanuts. It is large-seeded grass that can emerge from greater depths compared with other annual grasses. Chloroacetamide herbicides applied preemergence provide incomplete control.  While clethodim-type products can control this weed, timing is critical and sometimes we don't get complete control. Cadre and Impose also have activity but control is not always complete. If you have significant infestations of this weed and are in conventional tillage, consider preplant incorporated application of either Prowl or Sonalan. Look closely at the product label and use the higher-end rate for your soil.  Make sure you have adequate and uniform incorporation throughout the soil profile.