View Poster Application

Pigweed Control in Late Season Pastures

Extension Education

Adam Willis
CEA - Staff Chair
Jasper

Abstract

Pigweed (Amaranthus hybridus) is an invasive annual summer broadleaf weed that has no forage quality.  It is usually noticed by producers in mid to late summer when it starts reach moderate heights and produce seed heads.  It may have up to three germinations in a current growing season so persistence in control is extremely time consuming and important.Forage producers have many herbicide options for pig weed control in forage grass crops.  Our objective was to compare the effectiveness of common broad leaf herbicides late in the summer for pigweed control in forage grasses.  The demonstration was done late in the summer to see how much maturity and adverse conditions such as heat, and drought effected the control of pigweed.  Treatments were applied @ 15 gallons per acre.   Nonionic surfactant was added to all treatments at one quart per 100 gallons of spray mix.The best options for pigweed control fall into two options.  This is due to the negative effect of Metsulfuron on certain grasses such as fescue.  The cheapest option would be to spray Metsulfuron at the rate of 0.3 oz per acre costing $1.92 per acre, but this will cause damage to fescue that is present.  If fescue is present and if you are worried about damage to fescue then applying 24D at the rate of 1 quart per acre will provide excellent control at the cost of $6.94 per acre.  Both of these applications will provide 100% control of pigweed if applied correctly.The only reason for using more expensive herbicides is if you have additional weeds that are not readily controlled by Metsulfuron or 24D.  The cost per acre will increase but you are able to control multiple species with a single application.If pigweed has been allowed to go to seed in previous years, it will require multiple years of herbicide application to establish control.  This is due to the amount of viable seed in the soil that has built up to a higher level over years of no management.

Poster has NOT been presented at any previous NACAA AM/PIC

This poster is being submitted only for display at AM/PIC. Poster is not to be judged, but the abstract will be published in the proceedings.

Click to view Poster

Authors: Adam Willis
  1. Willis, A. CEA - Staff Chair, Newton County Cooperative Extension Service, Arkansas, 72641