Locust advice for agricultural industries

Australian plague locusts prefer to feed on green plant material. While grasses and cereals are most attractive to locusts, all pastures and field crops are at risk.

Where there is little green grass available, locusts will eat a wide range of horticultural crops including vegetables, grapevines and trees.

The following information provides advice to various agricultural sectors to assist landholders and growers in managing locusts on their land.

Apiaries and locusts

Both beekeepers and landholders share responsibility for managing the risk to bees when spraying locusts.

Bees can die by coming into direct contact with insecticides, or by insecticide residues brought back to the hive. If this occurs, entire colonies could die or be so weakened that honey production could cease until the colony recovers.

Landholders

Landholders who have beehives on their property should notify beekeepers of their intention to spray so that they can take steps to protect their bees before the spraying begins.

Read and follow chemical product labels

Agricultural chemical products that pose a risk to bees have specific prohibitive statements warning users to not spray when bees are present or foraging. Prohibitive statements are commonly found under the ‘Protection of Livestock, Fish, Crustacea and Environment’ or ‘Protection of Honey Bees and other Insect Pollinators’ sections of the label. The wording of these statements vary depending on the specific risks posed by the chemical. An example of a prohibitive statement is 'Dangerous to Bees – DO NOT spray any plants in flower while bees are foraging'.

Beekeepers

Beekeepers need to inform nearby landholders of the location of their hives and be easily contactable. Provide your contact details (including a mobile phone number) to nearby landholders and request that they contact you before spraying locusts. Stencil your mobile phone number onto your hives or place a sign with your contact details near your hives so that you can be contacted.

Note that landholders may not be able to provide you with 24–48 hours warning of their intention to spray. As bees regularly forage over long distances, it may also not be possible to know if chemicals have been, or will be, applied to properties within the bees’ flight range.

Regularly check the Australian plague locust update webpage for information on current locust activity in Victoria and if possible, move your bees to areas where locusts are not expected, as some insecticides can remain active for up to 28 days after application.

Honey bee pollination

If you are a beekeeper who contracts honey bee pollination services to growers, you may need to move hives during the pollination time to avoid risk of spraying. It is advisable to discuss moving hives with the grower to determine the possible impacts of removing bees under the conditions of the pollination contract.

Bees should not be returned to treated areas until all spraying in the bees’ foraging area is complete and after any chemical residue that may be harmful to bees have broken down. This could take at least 28 days for some chemicals.

Small-scale and hobby farmers and locusts

Small scale and hobby farmers are responsible for managing locusts on their properties.

Ground spraying using a chemical insecticide is the most successful method of managing locusts. There are chemical and biological insecticides available to small scale farmers wanting to protect their property from locust damage, see Managing Australian plague locusts.

Some small-scale landholders may not own the spray equipment needed to apply chemicals used to control locusts. You can either speak to neighbouring farmers to check whether they can assist you or contact a licensed commercial operator who can apply the chemical for you. If you have other small-scale landholders surrounding your property, see if you can coordinate your spray activities to occur at the same time.

All landholders should seek expert advice from their chemical reseller or agronomist as to which insecticide best suits their situation. As always, anyone planning to use an agricultural insecticide should ensure they use it safely by successfully completing a course in agricultural chemical use (available from local training organisations like TAFE).

Livestock, dairy farmers and locusts

Livestock and dairy farmer landholders are responsible for managing locusts on their properties.

Regular monitoring of pastures and fodder crops for locust activity and damage is recommended, as is keeping track of known locations of egg beds or previous egg laying activity. Newly sown grass pastures, shorter pasture species and crops that remain green for longer, such as lucerne, are particularly vulnerable.

Ground spraying using a chemical insecticide is the most successful method of managing locusts. There are chemical and biological insecticides available to livestock producers wanting to protect their property from locust damage, see Managing Australian plague locusts.

Landholders should seek expert advice from their chemical reseller or agronomist as to which chemical best suits their situation.

Chemical residues

All producers must safeguard against the risk of unacceptable agricultural chemical residues in agricultural produce (including grains, wool, meat and milk) in areas where locust control agents have been applied. Unacceptable residues can lead to restriction or closure of export markets. It is important for chemical users to read and understand the chemical product labels.

Unacceptable chemical residues can take impact livestock through:

• direct grazing on pastures or fodder crops that have been sprayed and withholding periods or label directions have not been followed
• direct grazing on pastures or fodder crops following a spray drift event
• feeding of fodder that has been exposed to spray drift.

If there is a risk that a feed shortage could occur, it is important to plan in advance:

• Conserve feed by cutting hay or silage (prior to spraying) so that it can be fed to stock
• Use your current hay and stockfeed reserves for feeding livestock while sprayed pastures are still within the grazing/fodder withholding period.
• Buy enough hay or stock feed for livestock until grazing/fodder withholding periods have expired (request a commodity vendor declaration from your supplier when purchasing any stock feed).
• You may need to organise a suitable feeding area (e.g. a laneway, sacrifice paddock, or stock containment area) if one doesn't already exist for your livestock. This area should not be adjacent to a watercourse or in an area where manure and effluent can reach a watercourse if it rains. Ensure stock have access to drinking water and shade during this period.

When spraying chemicals for locust control producers must follow withholding periods and grazing/slaughter intervals, where applicable, to ensure products are safe for human consumption and market access.

Withholding periods

A withholding period is defined as the minimum period of time that must elapse between the last application of a chemical product and the use of the agricultural produce to which the chemical was applied. This includes feeding on treated food, and the slaughter, collection, harvesting or use of the animal commodity for human consumption. The withholding period is mandatory for the domestic market and is provided on the label of all registered chemical products. The withholding period is designed to ensure that food and fibre derived from treated animals and crops complies with the maximum residue limits (MRLs) set by the Australian Pesticides and Veterinary Medicines Authority (APVMA).

Export Intervals

To provide guidance of appropriate withholding periods for export markets, several key export intervals have been specially developed by industry.

Export Animal Feed Interval (EAFI)

The minimum time which must elapse between the application of a chemical to a crop/pasture and grazing or harvesting of that crop/pasture as stock food for animals intended to be slaughtered for export.

Export Grazing Interval (EGI)

The minimum time that must elapse between the application of a chemical to a crop or pasture that is continually grazed and the slaughter of animals.

Export Slaughter Interval (ESI)

The minimum period of time that must elapse between chemical application to livestock and their slaughter for export purposes.

It is the responsibility of the owner of any agricultural produce that has been chemically treated to ensure compliance with that all relevant withholding periods.

If you intend to export treated produce check with your peak industry body, or the manufacturer of the product, for the latest information on maximum residue limits and import tolerances before using any products.

Producers should note that relevant maximum residue limits or import tolerances may not exist in export markets for chemicals they use on their produce, or they may differ from those established in Australia for domestic use.

All withholding periods and export animal feed intervals related to the harvest, grazing and cutting of crops for stock food are based on a chemical being applied to a crop/pasture that is still growing at the time of application and for the duration of the period or interval. This is because the breakdown of chemical residues in plants slows, and may stop, once the plant is no longer growing or alive.

It is advisable to delay the application of a chemical product to a crop/pasture, where a withholding period or export animal feed interval applies, unless the crop/pasture is still growing (green) at the time of application and unless expert advice is sought and this risk is managed, including pre-harvest residue testing.

Specific market advice can also be provided by your peak industry body, chemical reseller, agronomist or chemical manufacturer.

For more information about chemical residue limits see:

• Safe Meat
• Dairy Food Safety Victoria

Forestry landholders and locusts

Forestry landholders are responsible for managing locusts on their property.

Most tree species are susceptible to locust attack, including eucalypts, she-oaks, wattles and pines. Damage can be unpredictable and occur from hoppers that have developed on-site or nearby, or from adults flying onto the site. Locust hatchings are more likely to occur in plantations that are less than one year old, where bare ground is still available for egg laying.

Plantations with younger trees (less than three years old) are most at risk from attack because locusts prefer lush green feed. Severe defoliation can significantly reduce tree growth, which will affect the productivity of plantations. Trees planted individually or in narrow bands are particularly susceptible, but once plantation trees have developed a closed canopy, the risk of attack is generally lower.

Plantation managers should regularly monitor paddocks, tracks and firebreaks adjacent to the plantation for hopper activity.

Ground spraying using a chemical insecticide is the most successful method of managing locusts. There are chemical and biological insecticides available to landholders wanting to protect their property from locust damage, see Managing Australian plague locusts.

Forestry/plantation landowners should seek expert advice from their chemical or agronomist as to which insecticide best suits their situation.

When locusts are known to be in the area, protect tree plantings from hopper invasion by treating a band of crop/pasture around the edge of the plantation. While trees remain green, they are susceptible over the entire period that locusts are active and repeated spraying may be required. Ensure any treatment intervals on the chemical label are observed.

Organic farming and locusts

All landholders are responsible for managing locusts on their property.

It is strongly recommended that organic growers consult their organic certification agency regarding the use of locust treatment products.

There are biological insecticides registered for use in Australia for the control of Australian plague locust that are approved by organic certifying bodies. Green Guard® contains a naturally occurring fungus, Metarhizium, which is used as a biocontrol agent.The fungal spores attach to, and then penetrate, the locust body growing inside it until eventually causing the death of the insect. The fungus can take up to 20 days to kill the locust but can be applied in situations where conventional chemicals are not appropriate such as water ways and areas of high conservation value.

This mode of action is slower when compared to alternative chemicals such as organophosphates and synthetic pyrethroids (which stop locust feeding within a few hours and kills locusts within two or three days).

Green Guard® has been used for widespread control operations in Australia. However, it should be noted that while the use of a particular product may be acceptable under certain Australian certification standards, the standards applicable in other jurisdictions may differ.

Organic farmers should seek expert advice from their chemical reseller or agronomist as to which insecticides are available and best suit their situation.

Organic farmers should also speak to their neighbours who may use conventional chemicals to treat locusts which could potentially impact on the organic status of a farm. The establishment of buffer zones around sensitive areas may minimise risks and should be planned ahead of spraying.

Citrus growers and locusts

All citrus growing landholders are responsible for managing locusts on their property.

While locusts prefer to feed on grasses and cereal crops, they will feed on anything green if there is no alternative. Young citrus trees and citrus flush in particular, are susceptible to attack. Mature trees may also be affected. Citrus trees can tolerate a reasonable amount of leaf damage, but severe damage including defoliation, can hinder the tree’s growth and affect fruit quality and yield.

It is important for growers to actively monitor their property, including areas adjacent to their orchard, for hoppers, infestation and foliar damage. Orchard boundary areas are more likely to be damaged first and should be checked closely.

Ground spraying using a chemical insecticide is the most successful method of managing locusts. There are chemical and biological insecticides available to growers wanting to protect their property from locust damage, see Managing Australian plague locusts.

Citrus growers should seek expert advice from their chemical reseller or agronomist as to which chemical best suits their situation.

Spur-throated locusts

On occasion, the spur-throated locust has been known to attack citrus trees in Victoria, causing defoliation. The major breeding grounds for this species are the monsoonal tropical grasslands and central highlands of Queensland, but adult migrations in autumn have resulted in populations of this species occurring as far south as Victoria. Controlling spur-throated locusts is more difficult because they do not form bands. They are, however, much more susceptible to dry conditions and high mortalities are seen if regular rainfall does not occur.

Fruit and nut producers and locusts

Fruit and nut producers are responsible for managing locusts on their property.

The preference of locusts for green foliage makes immature trees more susceptible to damage. If young trees are stripped of foliage in spring, emerging shoots may be affected and tree shapes may need to be re-trained the following spring.

The reduction in foliage is likely to reduce tree size and yield, with fruit and nuts also sustaining some damage. The quality of the fruit and nuts may also be impacted by direct sun exposure as a result of the reduced foliage.

While mature trees are likely to experience little damage, any emerging buds, fruitlets or green nuts may be susceptible to damage from locusts. Mature trees usually recover from locust infestation and normal production can be expected to return by the next year.

Damage to orchards can be extensive as adult locusts can strip trees within hours. However, the extent of damage is unpredictable, as locusts may fly over some orchards and feed on others, giving a 'hit and miss' effect.

Boundary areas of orchards are most likely to be damaged first, so fruit and nut growers should monitor paddocks adjacent to the orchard for hoppers, in addition to monitoring trees for infestation damage.

Ground spraying using a chemical insecticide is the most successful method of managing locusts. There are chemical and biological insecticides available to growers wanting to protect their property from locust damage, see Managing Australian plague locusts.

If chemical insecticides are being applied to control locusts when trees are flowering, pollinators may be impacted. Bird or hail netting may provide some protection, particularly to fully enclosed orchards, however there have been reports of locusts damaging netting.

When choosing a chemical insecticide, consider prohibitive and restraint statements and withholding periods, particularly if treating crops close to harvest. Unacceptable residues in fruit or nut harvests can lead to restrictions on, or lead to, the closure of export markets to all Australian fruit and nut growers.

Using chemicals to control locusts may have an impact on a grower’s Integrated Pest Management program. The extent of the impact will depend upon the individual chemical selected by the grower. Monitoring insect levels (e.g. mites, thrips) after spraying is critical to ensure growers can quickly respond to any harmful insects that may arise.

Fruit and nut growers should seek expert advice from their chemical reseller or agronomist as to which insecticides are available and best suit their situation.

For more information on chemical residues see Chemical residues

Advice for exporters

If you are growing crops for export, check with your peak industry body or the manufacturer of the product for the latest information on maximum residue limits (MRLs) and import tolerances before using the insecticide.

Advice for providers of alternative stock feed

If you are a supplier of fruit or nut by-products for stock feed (e.g. pomace, seconds, hulls and shells), you will need to supply a commodity vendor declaration to your client so that they can avoid any potential unacceptable chemical residues.

Look out for bees

Some crops need insects to pollinate flowers and bee hives may be placed near or on your property to assist the pollination process. If you or your neighbours are in this situation, apiarists should be contacted and informed of your intention to spray, enabling them to manage the risk to their hives.

Some chemicals contain 'DO NOT' label statements that specifically prohibit the use of the chemicals when bees are foraging in the crop to be treated. Complying with these statements is a legal requirement. For more information about managing risks to bees, see Apiary section above.

Grain producers and locusts

Grain producers and landholders are responsible for managing locusts on their property.

Locust prefer young tender green shoots and leaves, but will also attack nearly mature crops if the tops are still green, causing the head of the grain to drop off.

Established green crops are susceptible to damage by adult locusts, but tend to be avoided by hoppers. Crops that are drying off when locusts begin to fly are also susceptible to damage while little, if any damage, is done to mature crops that have dried off.

The crops most at risk from locusts include wheat, barley and especially oats. While lupins, canola, chickpeas, field peas and faba beans are also susceptible while green, the following crop stages are at low risk of attack:

• canola (after the flowering stage)
• lupins (from pod bronzing)
• pulses (from pod yellowing)
• cereal crops (when completely dried off).

Ground spraying using a chemical insecticide is the most successful method of managing locusts. There are chemical and biological insecticides available to producers wanting to protect their property from locust damage, see Managing Australian plague locusts.

When choosing a chemical, factors such as crop type and use, sensitive areas and trade requirements need to be considered. Growers also need to consider and observe relevant withholding periods, particularly for crops close to harvest.

Landholders should seek expert advice from their insecticide reseller or agronomist as to which chemical best suits their situation.

Withholding periods

It is the responsibility of the owner of any agricultural produce that has been chemically treated to ensure compliance with all relevant withholding periods.

The harvest withholding period is the minimum time that must elapse between spraying the pasture/crop and harvesting the produce. The withholding period is provided on the label of all registered chemical products. Unless a withholding period is specifically listed for grazing or cutting, you must ensure that stock do not access treated areas, produce or crop waste.

Producers should note that relevant maximum residue limits or import tolerances may not exist in export markets for chemicals they use on their produce, or they may be different from those established in Australia for domestic use.

If you intend to export treated produce check with your peak industry body or the manufacturer of the product for the latest information on maximum residue limits and import tolerances before using products.

All withholding periods are based on a chemical being applied to a crop/pasture that is still growing at the time of application and for the duration of the period or interval. This is because the breakdown of chemical residue levels in plants slows, and may stop, once the plant is no longer growing or alive.

Do not apply a chemical product where a withholding period applies, unless the crop/pasture is still growing (green) at the time of application and unless expert advice is sought and this risk is managed, including pre-harvest residue testing.

Specific market advice can also be provided by your peak industry body, chemical reseller, agronomist or chemical manufacturer.

Receival standards for locust parts in grain

Bulk grain handlers have receival standards for locust body parts in samples, and for grain that has been damaged by locust feeding. Locust body parts may also change the smell and colour of the grain.

The detection of locust body parts upon delivery to grain receival centres may result in the grain being rejected or downgraded to feed quality. While it is possible the clean grain to remove locust body parts, this is time consuming and expensive, and may not be logistically possible during the harvest period.

Receival standards can be obtained from www.graintrade.org.au or individual grain traders.

Vegetables and herb growers and locusts

All vegetable and herb growers are responsible for managing locusts on their own property.

Locusts prefer to feed on young tender green shoots and leaves. Seedlings and younger crops are at higher risk, while crop varieties close to harvest and drying off will be relatively less affected.

Ground spraying using a chemical insecticide is the most successful method of managing locusts. There are chemical and biological insecticides available to growers wanting to protect their property from locust damage, see Managing Australian plague locusts.

The use of broad-spectrum controls will disrupt an Integrated Pest Management program. This may be particularly critical in situations where key pests have developed resistance to some broad-spectrum chemicals and other control options for these pests may need to be considered, if possible.

Growers must ensure they can control locusts while managing the risk of unacceptable chemical residues in their produce. Chemical residues that exceed the maximum residue limits (MRLs) for the intended market can potentially lead to the restriction or closure of export market access to those growers.

When choosing a chemical control option, growers need to consider and observe relevant withholding periods, particularly for crops close to harvest.

Growers should seek expert advice from their chemical reseller or agronomist as to which insecticide and what rates best suits their situation.

If growing crops for export, check with the manufacturer of the product and your state government for the latest information on maximum residue limits and import tolerances before using chemical controls.

Look out for bees

Some vegetable crops need insects to pollinate flowers and bee hives may be placed near or on your property to assist the pollination process. If you or your neighbours are in this situation, apiarists should be contacted and informed of your intention to spray, enabling them to manage the risk to their hives.

Some chemicals contain 'DO NOT' label statements that specifically prohibit the use of the chemicals when bees are foraging in the crop to be treated. Complying with these statements is a legal requirement. For more information about managing risks to bees, see Apiary section above.

Viticulture and locusts

All viticulturist landholders are responsible for managing locusts on their property.

When locusts are present in large numbers, all grapevines are at risk, with young tender vines and shoots the prime targets for attack. Large numbers of locusts can potentially strip grapevines of leaves within hours, however, the pattern of damage is unpredictable, as adult locusts may fly over vineyards to neighbouring properties, attacking some properties but missing others. Typically, the vineyard edges will show visual damage first as locust eggs are usually laid in bare ground along fence lines, headlands or roadsides.

The loss of leaves on grapevines from locust damage may impact on the ability of the plants to fully ripen. This may affect grape quality and productivity in the current season and can have a longer-term effect into the following season.

Young grapevines are at greater risk than mature grapevines, with effects ranging from retarded establishment and a delay in reaching the bearing stage through to the death of the vine. Although mature vines will survive a locust infestation, yield and quality could still be affected in later years.

Bunches of grapes may also be exposed to increased sunlight and heat due to the loss of foliage, which can increase the risk of sunburn and lower grape quality.

Mowing or applying herbicide to the grass between rows may reduce the feed supply for locusts. However, this may actually encourage the locusts to climb the grapevines and inflict greater damage on the canopy.

Ground spraying using a chemical insecticide is the most successful method of managing locusts. There are chemical and biological insecticides available to viticulturist landholders wanting to protect their property from locust damage, see Managing Australian plague locusts.

Viticulturists should seek expert advice from their chemical reseller or agronomist as to which insecticide best suits their situation.

Viticulturists are advised to check with the winery they supply before using any chemicals. When choosing a chemical control option, viticulturists need to consider and observe relevant withholding periods, particularly for crops close to harvest. Unacceptable residues can lead to restriction or closure of export markets.

Advice for exporters

Viticulturists and winemakers should note that maximum residue limits of import tolerances may differ to those in Australia or may not exist in export markets for grapes, vines or wine sprayed with insecticides to control locusts. Dried fruits may also have different tolerances relative to fresh grapes due to the drying process effectively concentrating any residual chemicals in the drying process.

If you are growing produce for export, check with your peak industry body or the manufacturer of the product for the latest information on maximum residue limits and import tolerances before using chemical products.

Advice for providers of alternative stock feed

Some vine products, such as grape marc, are fed to livestock as alternative sources of feed. It is vital that no unacceptable chemical residues remain in feed for livestock and that all applicable withholding periods are observed. Residues in animals may need to be considered, in addition to residues in the grape harvest. For more information, see the Livestock and dairy section above.

Spray equipment

Use a properly calibrated boom sprayer to apply insecticide while minimising the risk of sprays drifting outside target areas. If a boom sprayer has been used to apply herbicides, ensure all herbicide residues are cleaned out before spraying insecticides. Herbicide sprayers should preferably only be used for ground spraying, not for spraying directly onto vine foliage.

While slide-on engine driven misters (as opposed to vineyard misters) can apply chemicals efficiently, there is a greater risk of off-target chemical drift, increasing the risk of unacceptable residues in nearby crops, livestock, waterways, dams and other sensitive areas.

Nursery, ornamental and cut flower industry and locusts

Nursery owners and growers of cut flowers are responsible for managing locusts on their own land.

Locusts prefer young tender green shoots and leaves. Horticultural nurseries producing seedlings are potentially at risk of attack from adult locusts when in large numbers.

Ground spraying using a chemical insecticide is the most successful method of managing locusts. There are chemical and biological insecticides available to growers wanting to protect their property from locust damage, see Managing Australian plague locusts.

Using chemical insecticides to treat locusts will have an impact on a grower Integrated Pest Management (IPM) program. The extent of this impact will depend upon the chemical used by the grower as chemical insecticides may impact on beneficial species. Monitoring insect levels (e.g. mites, thrips) after spraying is critical to ensure growers can quickly respond to any harmful insects that may arise.

Nursery owners should seek expert advice from their chemical reseller or agronomist as to which insecticide best suits their situation.

Look out for bees

Beehives may be placed within or near nurseries or crops to assist the pollination process. In cases where insecticides (chemical or biological) need to be sprayed on nurseries or flower farms, the apiarist should be contacted and informed of your intention to spray, enabling them to manage the risk to their hives.

Some chemicals contain 'DO NOT' label statements that specifically prohibit the use of the chemicals when bees are foraging in the crop to be treated. Complying with these statements is a legal requirement. For more information about managing risks to bees, see Apiary section above.

Turf and parkland landholders and locusts

Turf and parkland landholders are responsible for managing locusts on their property.

Cultivated turf, sports grounds, golf courses and parklands are potentially at high risk of locust attack as short, green feed are preferred by Australian plague locusts.

Ground spraying using a chemical insecticide is the most successful method of managing locusts. There are chemical and biological insecticides available to landholders wanting to protect their property from locust damage, see Managing Australian plague locusts.

Turf and parkland landholders should seek expert advice from their insecticide reseller as to which insecticide best suits their situation.