Timing on Weed Control is Critical

Our human nature is to find a simple, one time solution for our problems. Unfortunately, this simple, one time solution does not exist for weed control in pastures and hay meadows. There are several factors that are important when it comes to weed control. These include:


Weed Identification: We cannot make the best management decisions if we don’t even know what the plant is we are trying to eradicate. Identification will determine the timing of our herbicide application along with the herbicide we choose. There are a multitude of

Maypop Passionflower

resources available to help with identification. County extension agents, extension specialist, websites (such as: https://nobleapps.noble.org/plantimagegallery/, http://rangeplants.tamu.edu/ ), books, etc. Identification is important since some herbicides are more effective on certain weed species than others. Correct identification of the target plant helps ensure the selection of the most effective herbicide as well as most effective time of application.


Sprayer Calibration: Sprayer calibration is a critical step for a pesticide applicator in making sure the correct amount of pesticide is applied to the target site. Calibration is the process by which the amount of pesticide being applied per unit of area is determined. This step is most often skipped because we get in a hurry, we calibrated it once a long time ago (surely nothing has changed) or we forget. By skipping sprayer calibration, the applicator may be applying too much pesticide or not enough pesticide. If too little pesticide is applied, the pest may not be controlled. Using more product than label directions recommend is illegal, may not control the pest effectively, may injure non-targets and may be hazardous to the environment. For a step-by-step guide to calibrating a sprayer see the following publication: Sprayer Calibration.


Timing of Application: Once we have identified the weed we can determine if the plant is an annual, biennial or a perennial. Growth pattern will influence our timing to maximize control as well as reduce future populations. Annual plants, like wooly croton, complete their life cycle in one year/season. Ideal time to spray annual weeds with herbicide is when they are small and growing, well before they produce any flower or seed. Perennials complete their life cycle in multiple years/seasons. They often reproduce by seed and can regrow from root structures. An example of a perennial is blackberry/dewberry. Most perennials need to be sprayed with a herbicide at blooming or shortly thereafter. Identification will help determine the best time to be the most effective with given herbicides.


Follow the Label Directions: Strict adherence to label directions is required by law. Paying close attention to label directions will also ensure safe, effective, and economical use. Herbicide labels contain directions for proper rate and timing of application, a list of susceptible species, and information regarding cleanup and disposal following use.


Remember: The label is the law. Always read the pesticide label before using.



Vanessa Corriher-Olson

Professor, Forage Extension Specialist

Texas A&M AgriLife Extension

Overton, TX

Soil & Crop Sciences Department



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