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Turf Culture

Odessa Herbicide (onion weed treatment)

Odessa Herbicide (onion weed treatment)

$98.00
$98.00
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Odessa herbicide is a premium, selective post-emergent weed killer which treats a wide range of broadleaf & grassy weeds in lawns including waxy and hard to kill varieties such as Onion Weed.

What it Controls

Odessa targets a wide variety of durable weeds in lawns including:

  • Bindii (Soliva sessilis),
  • Black thistle (Cirsium vulgare),
  • Cat's ear (Hypochoeris radicata),
  • Cotula (Cotula australis),
  • Cudweed (Gnaphalium sp.),
  • Guildford Grass (Onion Grass) (Romulea rosea),
  • Medic (Medicago spp.),
  • Mouse ear chickweed (Cerastium vulgatum),
  • Oxalis (Oxalis corniculata),
  • White Clover (Trifolium repens),
  • False onion weed / Fragrant false garlic / Onion weed (Nothoscordum gracile, fragrans or borbonicum)
  • Ryegrass, perennial (Lolium perenne)

Why it's Popular

Targeted Weed Control: Effectively treats stubborn waxy leaf weeds such as Oxalis and Guildford Grass that other weed killers struggle to eliminate.

Safe on Lawns: Can be used on a wide range of turf varieties including Buffalo, Couch (Not QLD Blue) and Kikuyu.

Systemic Action:  It is absorbed by foliage and shoots then rapidly translocated through the plant and acts by inhibiting acetolactate synthase (ALS) to ensure complete eradication of the weed.

Key Features

  • Outstanding post emergent control of difficult to kill weeds Onion weed, Guildford grass (Onion grass)
  • Excellent Turf Tolerance on Common Couch, Hybrid Couch, Buffalo and Kikuyu (DO NOT use on Queensland Blue Couch)
  • Selectively controls of Ryegrass out of Common Couch, Hybrid Couch, Buffalo and Kikuyu
  • Controls a unique scope of difficult to kill weeds
  • Low odour
  • Low poison schedule (Schedule 5 - CAUTION)

Active Ingredient

  • 100 g/kg iodosulfuron-methyl-sodium

Application and Dosage

  • 0.25 to 1.5g per 100sqm
  • 50g pack treats 3300+ sqm of lawn
  • Spray onto a dry lawn with a pressure sprayer and let it dry. Do not water product in. Avoid mowing at least 4 days before and after spraying.
  • For optimal control mix in a surfactant such as Wetter 600, particularly important with stubborn, waxy weeds.

Odessa Cost Per Application - Cost per 100sqm at a rate of 1.5g per 100sqm is $2.97 including GST

More Information

Odessa Herbicide allows turf managers to control the various difficult weeds that other herbicides have struggled to manage such as Guildford Grass (Onion Grass) (Romulea rosea) in Common Couch, Hybrid Couch, Buffalo or Kikuyu turf stands.

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Frequently Asked Questions

What is Odessa Herbicide used for?

Odessa Herbicide is a selective turf herbicide designed to control difficult weeds such as onion weed (false garlic), Guildford grass (onion grass), oxalis, clover, bindii, and other broadleaf and grassy weeds in established lawns.

Why is onion weed so hard to kill in lawns?

Onion weed grows from bulbs underground, which allows it to regrow even after mowing or pulling. Effective control requires a herbicide that penetrates into the bulb system rather than only treating the visible foliage.

How does Odessa Herbicide work on onion weed?

Odessa Herbicide works systemically, meaning it is absorbed through the leaves and transported down into the bulb or underground storage structures. This allows it to kill onion weed at the source instead of just removing top growth.

Is Odessa Herbicide safe for my lawn?

Odessa Herbicide is safe for most established warm-season turf grasses such as couch, kikuyu, buffalo, and hybrid couch when used according to label directions. It should not be used on Queensland blue couch.

Can Odessa Herbicide kill onion grass (Guildford grass)?

Yes, Odessa Herbicide is specifically effective against onion grass (Guildford grass). It is designed to target both the foliage and the underground bulb system, making it one of the more effective selective options for this weed in turf.

How do you apply Odessa Herbicide for onion weed?

Odessa Herbicide is applied as a foliar spray using a calibrated sprayer. Even coverage of actively growing leaves is important. For best results, follow label rates carefully and avoid over-application.

When is the best time to treat onion weed with Odessa Herbicide?

The best time to apply is during active growth, typically in autumn through early spring. This is when onion weed is most actively transporting nutrients to its bulb, allowing better herbicide uptake.

How long does Odessa Herbicide take to work on onion weed?

Odessa Herbicide works gradually with full control sometimes taking up to 4–6 weeks depending on conditions and weed maturity.

Do I need a wetting agent with Odessa Herbicide?

Yes, a surfactant (such as Wetter 600) is often recommended to improve leaf coverage and absorption, especially on waxy or upright weeds like onion weed.

Can I pull onion weed out instead of using herbicide?

Hand pulling is not effective because bulbs often break off underground and regrow. This is why systemic herbicides like Odessa are preferred for long-term control.

Is Odessa Herbicide rainfast?

Yes, once fully absorbed, Odessa Herbicide becomes rainfast. However, avoid watering or rainfall immediately after application to ensure the herbicide has time to dry on the leaf.