Weeds in hay and grain – Is there something new on your farm?

By Callen Thompson, Senior Land Services officer – Mixed Farming

Over the last twelve months, we have seen trucks carting hay and grain into the central west from all over the country. Now that we are getting a bit of rain, it is a good time to get out and have a look at what weeds are coming up in areas that fodder has been fed out or stored. Our recommendation is: Monitor – Identify – Control


Hopefully all producers have a farm biosecurity plan, which included limiting the area that hay is spread and making feedout and storage areas on a farm map. If this has been done, it makes it a lot easier to get out and monitor these areas for weeds.

It is also important to monitor paddocks that stock have had access to as some seed can be viable after traveling through the digestive system. Using confined feeding or a sacrifice paddock makes this much easier. While you are looking for weeds, check roadways where fodder has been carted as well as waterways and timbered areas as feral and native animals may be helping themselves to your brought in fodder.

Lastly, if you know that your neighbour has been feeding stock it might be advisable to check your fencelines. Ideally you should monitor for weeds 12 days after a seasonal break rainfall event and you should continue doing this for at least two years.


Knowing where your hay has come from, having a vendor’s declaration and looking for weeds in the hay as you feed it out will give you an idea of what to look out for.

If you see anything unusual contact your agronomist, your local council weeds officer or your Local Land Services biosecurity officer/Ag advisor. If you suspect Herbicide resistant weeds have entered your property speak to Local Land Services Ag Advisory staff or your agronomist about getting them tested.

Some of the weeds of concern are described below, but there are many more. Remember if it is something unusual, get it identified!

Parthenium Weed

DescriptionParthenium weed is an annual plant with a deep taproot and an erect main stem. The weed usually grows to a height of 1–1.5m although it can grow to 2 m high.

Why is it a problem? Parthenium weed adversely affects human and animal health and can cause:

  • respiratory problems
  • severe dermatitis
  • tainted meat if stock eat the plant within one month of slaughter
  • tainted milk.

Scientific name: Parthenium hysterophorus

State found in: Endemic to central Queensland and is spreading into southern Queensland

Type of hay it could be found in: Rhodes grass, Forage sorghum

Herbicide resistance: NA

Wild Radish

DescriptionWild radish is an upright herbaceous plant usually growing 40-100 cm tall, Distinguished from turnip weed by purple veins on flowers and hair on mature leaves

Why is it a problem? Populations from WA and SA have high levels of herbicide resistance. If these populations were introduced into NSW they would be difficult to control in winter cropping systems.

Scientific name: Raphanus raphanistrum

State found in: Currently in NSW but populations from WA and SA have high levels of herbicide resistance

Type of hay it could be found in: Legume, cereal, rye, pasture or canola hay and winter grain crops

Herbicide resistance: Group I, B, C and F

Annual Ryegrass

Description: Rye grass has a narrow inflorescence of numerous small spikelets, 4-18 mm long, which are arranged alternately up the inflorescence. The leaves are shiny on one side and dull on the other.

Why is it a problem?Populations from WA, SA and Vic have high levels of herbicide resistance. If these populations were introduced into NSW they would be difficult to control in winter cropping systems

Scientific name: Lolium rigidum

State found in: Widespread in NSW but populations from WA, SA and Vic have higher levels of herbicide resistance. Herbicide resistance is present in NSW and care should be taken when buying any hay with the potential to have ryegrass seed in it.

Type of hay it could be found in: Legume, cereal, rye, pasture or canola hay and Winter grain crops

Herbicide resistance: Group M, A, B, D, J, K

Gamba Grass

DescriptionGamba grass is tropical species that grows in dense stands up to 4m high

Why is it a problem?Gamba grass was introduced as a pasture species and while it is palatable when it is young, its fast growing nature and poor feed quality as it matures makes it difficult to manage and it will quickly become rank and unpalatable. Gamba is an environmental weed and will quickly establish in natural areas. It then becomes a fire risk. Gamba grass could be a considerable threat to ecosystems like the Macquarie Marshes.

Scientific name: Andropogon gayanus

State found in: Darwin and Katherine and Douglas Daly regions of the Northern Territory

Type of hay it could be found in: Jarra Grass

Herbicide resistance: NA


Weeds such as Parthenium weed or gamba grass are notifiable to the NSW Department of Primary Industries (DPI) on 1800 680 244.

DPI’s WeedWise website allows you to search for a weed and look up your duty in regards to biosecurity.

If you have identified weeds that are new to your property, control them early to prevent seed set. If practical, manually remove weeds (avoid contact with Parthenium weed). If chemical control is warranted, speak to your agronomist or adviser and always follow the label directions. It is important to re-inspect the area to make sure all weeds are controlled

The current environmental conditions have dictated the need to bring in fodder to feed livestock and there is a very good chance that some of the hay brought in has weeds in it. It is important to monitor areas where fodder has been used so you can identify and control any weed incursions quickly so they do not have an economic impact on you or your neighbours. There is support available from both Local Land Services and regional councils to assist producers to identify weeds and provide tactics for control.

If you see anything unusual, contact your local Local Land Services Ag advisory staff member or biosecurity officer.

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