Early Season Paraquat Drift on Rice

Off target drift of paraquat has increased with the use of paraquat burndown behind the planter for resistance management.  Under the direction of Dr. Jason Bond, evaluating the effects of early season paraquat drift on rice has been the dissertation project for PhD candidate, Ben Lawrence.  During the past four seasons, Ben has applied a simulated drift rate to rice at different growth stages.  MSU currently recommends a burndown rate of 48 ounces at planting.  Ben’s studies were conducted utilizing a 1/10^th use rate or 4.8oz of paraquat.  Presented are the results.

Applications were made to rice from emergence to panicle differentiation or approximately ½” internode elongation.

Maturity was delayed with each application timing from 6 days to 13 days with the panicle differentiation (1/2″ internode) stage application never reaching maturity.  In this study, yield losses ranged from 6.5% at the VEPOST treatment to approximately 92% at the panicle differentiation treatment timing.

Ben also included in the study paraquat plus residual combinations.

In this study rice injury from drift rates of metribuzin and formesafen applied alone were less than 10%.  Rice injury of 50% can be observed from applications of paraquat alone, or when applied with fomesafen.  Greater rice injury can be expected when paraquat is applied with metribuzin.  For more information concerning this study, Dr. Bond can be contacted at Phone: (662) 769-0268 or by email at  jason.bond@msstate.edu