Australian plague locust: insecticide spraying guide

Page last updated: Friday, 26 November 2021 - 7:38am

Please note: This content may be out of date and is currently under review.

The following article provides information on spraying and withholding periods for the Australian plague locust.

These withholding periods only apply if you are selling livestock or harvesting crop that has been sprayed for locust.

If livestock are retained on farm, withholding periods do not apply.

Spraying thresholds

When spraying locusts, consideration must be given to the value of pastures and crops in the context of the whole farm. This includes the number of livestock, available feed supplies and feed requirements, the cost of replacement feed, if stock have to be sold and the cost of locust control.

Pastures

Implement control measures if pasture is valued at the cost of replacement feed for livestock and locust numbers exceed the following thresholds:

  • 20 hoppers /m2
  • 10 adult locusts /m2

Grain crops

Established green crops tend to be avoided by hoppers (although the edges of crops can be damaged). Crops that are beginning to dry off when locusts begin to fly are especially susceptible to damage.

Hopper and adult locust numbers should be closely monitored, and if any damage is seen, then spraying should start immediately.

Key points

  • To prevent unacceptable residues of chemicals in livestock at the time of sale be aware of the withholding periods (WHP) and export intervals (EAFI, ESI, EGI). Use the Witholding period tables to select the insecticide best suited for your enterprise.
  • Label withholding periods only apply to domestic markets. EAFIs, ESIs and EGIs do not appear on the product label.
  • Organophosphorus and carbamate insecticides break down relatively quickly while the synthetic pyrethroid insecticides can persist on pastures and crops for relatively long periods, particularly on drying or dry pastures and crops. The synthetic pyrethroid esfenvalerate is an exception and does not persist on dry pasture.

National vendor declaration

If livestock have been exposed to insecticides within 60 days of selling, answer yes to question 7 on the cattle National Vendor Declaration (NVD), or yes to question 5 on the sheep NVD. Complete the details of the chemicals used as required (except for synthetic pyrethoids used on drying pasture where the 60 day period commences after the next break of season).

What are the withholding periods?

Harvest withholding period

When can I harvest a sprayed crop?

  • Observe the harvest withholding period, WHP(H), before harvesting a sprayed crop.

Livestock withholding period

When can I move livestock back onto sprayed pastures?

  • Domestic market: observe the grazing withholding period, WHP(G), before moving livestock back into a sprayed pasture.
  • Export market: observe the export animal feed interval (EAFI) before grazing the pasture.
  • If you are intending to sell livestock and do not know which market livestock are destined for, assume it will be the export market.

When can I harvest sprayed crop or pasture for animal feed?

  • Domestic market: observe the harvest withholding period, WHP(H), before harvesting the crop or pasture for animal feed.
  • Export market: observe the export animal feed interval (EAFI) before harvesting the crop or pasture for animal feed.
  • If you are intending to sell livestock and do not know which market livestock are destined for, assume it will be the export market.

When can I sell livestock that has been fed on sprayed pasture?

  • Domestic consumption and export market: If livestock are moved back onto pastures before the WHP(G) or EAFI has elapsed, observe the export grazing interval (EGI - refer to the footnote below).

​When can I sell livestock that has been over-sprayed?

  • Where possible avoid spraying areas in which livestock are feeding.
  • Domestic consumption and export market: if over-spraying of livestock is unavoidable, and grazing continues on the sprayed pasture, observe the (EGI - refer to the footnote below).
  • If over-spraying of livestock is unavoidable, and livestock is removed to clean pasture, observe the export slaughter interval (ESI).

Footnote

Some synthetic pyrethroids (SPs), such as cypermethrin, alpha-cypermethrin, lambda-cyhalothrin, gamma-cyhalothrin and beta-cyfluthrin, may persist on dry pasture or in harvested and stored animal feed (for example, hay) for long periods. If spraying drying pasture with SPs the EGI does not apply. Stock must graze clean feed for the ESI period before sale for slaughter for export. Similarly, feed harvested from pastures or crops treated when drying off or while dry may have unacceptable levels of animal feed residues. The pasture, or crop, must be regarded as contaminated until such time as there has been substantial regrowth (for example, following good rains or the autumn break). If livestock are expected to be sold for slaughter before the break of the next season and alternative feed is unlikely to be available, it would be wise not to use SPs mentioned above.

Withholding period tables

The following tables give withholding periods (days) for different chemical groups.

The withholding periods and export intervals are only accurate if chemicals are used at the label recommended rates.

See below for footnote and definitions.

Withholding period for organophosphates

Chlorpyrifos (for example, Lorsban) withholding periods (days)
  Pa Ce Ca Lu Pu EAFI ESI EGI
Harvest: WHP 2 10 10 10 10
Grazing - local: WHP 2 2 2 2 2
Grazing - export: WHP 0 56 56
Diazinon (for example, Diazinon, Diazol) withholding periods (days)
  Pa Ce Ca Lu Pu EAFI ESI EGI
Harvest: WHP 14 14 14 14
Grazing - local: WHP 14 14 14 14
Grazing - export: WHP 14 14 28
Fenitrothion (for example, Fenitrothion, Sumithion) withholding periods (days)
  Pa Ce Ca Lu Pu EAFI ESI EGI
Harvest: WHP 14 14 14
Grazing - local: WHP 14 14 14 14 14
Grazing - export: WHP 14 14 14
Maldison (for example, Maldison, Hy-Mal) withholding periods (days)
  Pa Ce Ca Lu Pu EAFI ESI EGI
Harvest: WHP 1 1 0 3
Grazing - local: WHP 1 1 0
Grazing - export: WHP 1 1 1

Withholding period for carbamates

Carbaryl (for example, Bugmaster, Carbaryl) withholding periods (days)
  Pa Ce Ca Lu Pu EAFI ESI EGI
Harvest: WHP 1 1
Grazing - local: WHP 1 1
Grazing - export: WHP 7 7 7

Withholding period for synthetic pyrethroids

Alpha-cypermethrin (for example, Dominex, Fastac) withholding periods (days)
  Pa Ce Ca Lu Pu EAFI ESI EGI
Harvest: WHP 14 7 21 28 28
Grazing - local: WHP 3 14 21 35
Grazing - export: WHP 42 56 (see footnote below)
Beta-cyfluthrin (for example, Bulldock) withholding periods (days)
  Pa Ce Ca Lu Pu EAFI ESI EGI
Harvest: WHP 3 14 14 14 7
Grazing - local: WHP 3 7 14 7 7
Grazing - export: WHP 42 56 (see footnote below)
Cypermethrin (for example, Sonic, Scud) withholding periods (days)
  Pa Ce Ca Lu Pu EAFI ESI EGI
Harvest: WHP 21 21 28 28
Grazing - local: WHP 35 21 35
Grazing - export: WHP 63
Esfenvalerate (for example, Sumi-Alpha) withholding periods (days)
  Pa Ce Ca Lu Pu EAFI ESI EGI
Harvest: WHP 7 7 14 14 14
Grazing - local: WHP 7 7 7 7 7
Grazing - export: WHP 14 14 14
Lamda-cyhalothrin (for example, Karate) withholding periods (days)
  Pa Ce Ca Lu Pu EAFI ESI EGI
Harvest: WHP 14 14 7 14 7
Grazing - local: WHP 14 14 7 14 7
Grazing - export: WHP 42 56 (see footnote below)
Gamma-cyhalothrin (for example, Trojan) withholding periods (days)
  Pa Ce Ca Lu Pu EAFI ESI EGI
Harvest: WHP 14 14 7 14 7
Grazing - local: WHP 14 14 7 14 7
Grazing - export: WHP 42 56 (see footnote below)

Withholding period for pyrazoles

Fipronil (for example, Regent) withholding periods (days)
  Pa Ce Ca Lu Pu EAFI ESI EGI
Harvest: WHP 14
Grazing - local: WHP 14
Grazing - export: WHP 14 14 21

Withholding period for biological control

Metarhizium anisopliae var acridum (for example, Green Guard) withholding periods (days)
  Pa Ce Ca Lu Pu EAFI ESI EGI
Harvest: WHP 0 0 0 0 0
Grazing - local: WHP 0 0 0 0 0
Grazing - export: WHP

Footnote

Some synthetic pyrethroids (SPs), such as cypermethrin, alpha-cypermethrin, lambda-cyhalothrin, gamma-cyhalothrin and beta-cyfluthrin, may persist on dry pasture or in harvested and stored animal feed (for example, hay) for long periods.

If spraying drying pasture with SPs the EGI does not apply.

Stock must graze clean feed for the ESI period before sale for slaughter for export.

Similarly, feed harvested from pastures or crops treated when drying off or while dry may have unacceptable levels of animal feed residues. The pasture, or crop, must be regarded as contaminated until such time as there has been substantial regrowth (for example, following good rains or the autumn break).

If livestock are expected to be sold for slaughter before the break of the next season and alternative feed is unlikely to be available, it would be wise not to use SPs entioned above.

Important points to note

What are the main risks or dangers that growers need to be wary of?

Chemicals used according to label recommendations will meet Australian market requirements, but not export market requirements. Some chemicals can last long periods in dry conditions (see footnote below). Only use chemicals on crops they are registered for.

What can growers do to avoid chemical residues impeding their ability to sell stock?

Plan when you aim to sell stock. Select paddocks to graze these animals and only use sprays (if any) that will be gone by the time you wish to sell animals. That is those with an ESI or EGI that ends before you wish to sell the animals. Select chemicals with shorter ESI and EGI such as fipronil or fenitrothion.

Definitions

Pa = pasture
Ce = cereal
Ca = canola
Lu = lupins
Pu = pulses (check the registered label to ensure your pulse crop is listed) quoted for field peas

x = no information available for this withholding period

Grazing withholding period (WHP(G))

The number of days that must elapse between application of insecticide and grazing of livestock (domestic market only).

Harvesting withholding period (WHP(H))

The number of days that must elapse between application of insecticide and harvest or harvest and feeding of harvested pasture/crop to livestock (domestic market only).

Export animal feed interval (EAFI)

The minimum period that must elapse between the application of a chemical and grazing or harvesting the crop/pasture for animal feed.

Export slaughter interval (ESI)

The minimum period that must elapse between removal of grazing livestock to clean pasture or feed and slaughter, where the livestock have been grazing the crop/pasture prior to expiry of the export animal feed interval (EAFI).

Export grazing interval (EGI)

The minimum period that must elapse between the application of chemical and slaughter of the stock, where grazing has continued on the crop/pasture from the time the chemical was applied.

Contact information

Pest and Disease Information Service (PaDIS)
+61 (0)8 9368 3080