Weed Control and Peanut ( Arachis hypogaea L.) Cultivar Response to Encapsulated Acetochlor

ABSTRACT Field studies were conducted during 2011 and 2012 in the Texas peanut production regions to evaluate encapsulated acetochlor for weed control and cultivar response. Acetochlor alone applied preemergence (PRE) controlled horse purslane, Palmer amaranth, smellmelon, and Texas millet as well as flumioxazin or S-metolachlor. The addition of pendimethalin to either acetochlor, flumioxazin, or S-metolachlor did improve weed control in some instances. In another study comparing the three above mentioned herbicides alone or followed by lactofen postemergence (POST), the addition of lactofen to acetochlor, flumioxazin, or S-metolachlor improved control of smellmelon and Palmer amaranth in some instances but did not affect horse purslane control. In a tolerance study to evaluate potential differences in variety response to acetochlor at 1.26 (1X) and 2.52 kg ai/ha (2X) applied preplant incorporated (PPI), PRE, early postemergence (EPOST), or POST, peanut yield or grade was not affected by either rate of acetochlor or application timing.