Weed warning after drought, fire and flood

The risk of weed invasion, and their impact on farms and the environment dramatically increases during and after an emergency such as drought, fire or flood. This is when you refer to your current Biosecurity Plan.

The problem is often compounded, as dealing with other pressing emergency response and recovery issues, the spread of weeds can often be overlooked.

It is not until some months after the emergency that it becomes obvious that weed impact may be a costly legacy to the farmer.

To minimise this risk, you can implement some simple actions which may save money, environmental values and avoid future stress whilst recovering from an emergency.

The activity that poses the greatest risk of weed invasion during and after an emergency is the movement and importation of hay and grain as stockfeed onto farmland. Be especially careful of feed imported from interstate and other Victorian regions which could carry new weeds into Victoria.

Stockfeed on farm

Check the origin of your hay or grain stockfeed:

  • Has it come from a known weed-infested area?
  • Ask the supplier for a written Commodity Vendor Declaration on any potential weed content.

Where possible source locally grown feed to reduce the chance of introducing new weeds that are not already present and known in your locality.

Keep records of purchased hay or grain stockfeed:

  • content
  • location sourced
  • producer
  • date purchased
  • transporter and
  • feed-out area.

Feed-out in a confined area away from drainage lines (stock containment areas) to reduce the likelihood of weeds being spread throughout your property.

Monitor feed-out areas regularly and be suspicious of unfamiliar plants that germinate.

Transporting hay or grain stockfeed

  • Care should be taken to avoid the spread of weeds onto road reserves and adjacent land.
  • Vehicles should be cleaned down after deliveries.
  • Vehicle cleaning should occur in a designated area to prevent weed dispersal and contain new infestations for easier management.
  • During drought, keep an eye on local roadsides and for 12 months afterwards, to detect new weed infestations.

Stock

  • Building up stock numbers when recovering from an emergency is also another high risk activity that can introduce weeds.
  • Quarantine new stock for 3 to 4 days into a small paddock for monitoring, allowing time for viable seeds to pass through the animal. This will confine weed seeds to one area for ongoing management.
  • Check for weed seed in fleece and continue to check for the weeds in areas with new stock.
  • Where possible, purchase shorn sheep.
  • When moving stock along roadsides try to avoid travel through known weed infestations.
  • Monitor stock routes during drought and for 12 months afterwards, to detect new weed infestations.

Other weed-spread risks during emergency and recovery

Drought

  • Ensure that vehicles and equipment of contractors and advisors are clean and free of weeds before entering and leaving your property to clean dams, cart water or carry out other works which, in the case of drought or fire, take advantage of the dry conditions.
  • Use contractors that are accredited in vehicle and machinery hygiene.

Fire

  • Firefighting activities may spread weeds — monitor areas burnt by wildfire for weed germination.
  • Ensure that vehicles and equipment of contractors and advisors are clean and free of weeds before entering and leaving your property to replenish water supplies, rehabilitate fire breaks, clear fence lines and re-establish vegetation.
  • Weed seeds can also be easily spread by water flow across bare ground during rain events.

Flood

  • Weed propagules can be dispersed in flood waters. Monitor areas previously flooded for 12 months afterwards to detect new weed infestations.
  • Weed propagules can easily attach to vehicles and equipment in muddy conditions and when being moved between properties to repair flood damage and assist with recovery, they can pose a high risk of weed spread. Ensure that vehicles and equipment of contractors and advisors are clean and free of weeds before entering and leaving your property.

More information

For further information on minimising weed spread, and weed identification and control, contact your local Agriculture Victoria office or call the Customer Service Centre on 136 186.

Page last updated: 19 Jun 2020