Controlling Costly Weeds in Citrus Groves

Close-up of oranges in a citrus grove

A strong weed management program is an essential component to ensuring a successful and healthy citrus crop — especially considering the impact of missed weeds on groves.

Weeds compete with citrus trees for vital nutrients, water and light, slowing tree growth and increasing vulnerability to insect and disease damage, according to the University of California, Davis. But California citrus growers can promote stronger trees by following best practices for effective weed management.

Don’t Wait Until it’s Too Late

Take preventive action by using pre-emergent weed control options before a major issue occurs. Pre-emergent herbicides can serve as an additional mode of action to control herbicide-resistant weeds and avoid future weed resistance.

Effective, long-lasting products such as Alion® herbicide from Crop Science can help growers focus on weeds before they strike, resulting in greater flexibility in post-emergent treatment and a reduction in early season competition between weeds and citrus trees.

Combat Existing Weeds

Once weeds have started to emerge, timing is essential to manage the threat. If a post-emergent herbicide application is late or missed, controlling those weeds becomes significantly more difficult. When combatting post-emergent weeds, using the right herbicide — based on its efficacy against the specific weed species — is key.

Follow the Use Rates on the Label

Although some growers might initially find success managing weeds with rates that are lower than those recommended on the label, it is important to follow label rates to avoid the development of resistant weeds. Low dose applications have the potential to allow controllable weed species to escape, leading to resistance.

Dr. Roy Whitson, Technical Service at Bayer, likens it to the application of sunscreen — herbicides should be applied sufficiently and thoroughly and then reapplied according to the label. He also advises that herbicide rates should be at or near the maximum use rates when used alone.

Fight Resistance

Over time, controllable weed species will develop resistance to herbicides if the right precautions are not taken. Growers can fight weed resistance with a smart, integrated weed management program employing different herbicides with multiple modes of action. Repeated use of the same herbicide mode of action without periodically rotating to a different one can lead to resistance. Make sure to develop an effective chemistry rotation plan to safeguard the long-term efficacy of multiple herbicides.

Be Vigilant

After applying herbicides, growers should look for signs that weeds have been controlled. Weed threats exist throughout the season, so it is vital to monitor groves for potential weed issues that might arise. The cost of missed weeds is enormous, possibly leading to lower yields.

Learn more about weed management and how a long-lasting, pre-emergent solution like Alion can help keep citrus groves clean.

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