The Effect of 2,4-Dichlorophenoxyacetic Acid (2,4-D) on Peanut whenApplied During Vegetative Growth Stages

摘要

The development of 2,4-D-resistant cottonand soybean cultivars has created great concernabout the potential off-target movement of 2,4-Donto sensitive broadleaf crops. Peanut is oftengrown in close proximity to cotton and soybean.Therefore, field studies were conducted during2012 and 2013 at Plains, Ty Ty, and Attapulgus,GA to evaluate peanut response to 2,4-D at 67,133, 266, 533, and 1066 g ae ha1 applied atpreemergence (PRE), 10, 20, or 30 d afterplanting (DAP), corresponding to PRE, V2, V3,and V5 peanut growth stages. Nontreated controls(NTC) were included for comparison.Treatment timing by rate interactions weresignificant (P , 0.0001). As 2,4-D rate increasedpeanut injury increased. There was variation inyield loss response dependent on peanut growthstage at application timing. Peanut that wastreated preemergence and at the V2 growth stagedid not have yield loss at any of the 2,4-Devaluated rates (67 to 1066 g ha1) relative to theNTC. When peanut was treated at V3 and V5growth stages with 2,4-D, injury estimates were 5to 32% from the 67 to 1066 g ha1 ratesrespectively, and peanut canopy diameter wasstunted 5 to 35% at the same rates. The resultingpeanut yield loss was 23 and 36% from 533 and1066 g ha1 of 2,4-D applied at V3 and V5 growthstages; in part due to reproductive growth beinginitiated during that time-frame and peanut hadless time to recuperate before harvest. Linearregression models were used to evaluate peanutinjury and peanut yield results. Significantcorrelations were established for V3 and V5treatments between injury and yield, injury andcanopy diameter, and canopy diameter and yield(P , 0.0001), with correlation coefficients of 0.48, 0.76, and 0.51, respectively. Growersand extension agents will be able to use thesepeanut injury estimates and canopy diameter datato make improved predictions of potential peanutyield loss where off-target movement of 2,4-D orsprayer contamination has occurred.