Peanut Response to Simulated Carryover of Terbacil

Abstract

Current label restrictions prohibit the planting of peanut for two years after an application of terbacil in watermelons. Thus, research was conducted from 2016-2018 to determine peanut response to terbacil with the ultimate goal of reducing the current rotation restriction. Small-plot replicated field trials were conducted near Ty Ty, Georgia. Terbacil was applied preemergence (PRE) to peanut (cv. Georgia-06G) at the following rates: 28, 56, 112, and 224 g ai/ha. Terbacil use rates in watermelon range from 112 to 224 g ai/ha. A non-treated control (NTC) or 0 g ai/ha rate was included for comparison. Peanut density/stand was not reduced by any rate of terbacil. With the exception of the 56 g ai/ha rate at 28 days after planting (DAP), the only rates of terbacil that caused significant visual peanut injury were the 112 g ai/ha and 224 g ai/ha rates. Injury at these rates ranged between 12% and 81%. The 224 g ai/ha rate caused more peanut injury than the 112 g ai/ha rate. The injury caused by terbacil at 112 g ai/ha and 224 g ai/ha resulted in significant peanut yield losses of 28% and 70%, respectively. Peanut yield losses from terbacil were only observed from the typical range of watermelon field use rates. Consequently, these results suggest that peanut could be safely planted following terbacil after approximately two field half-lives or approximately 240 d have occurred.