Frequently asked questions - plague locusts
Spring 2010 Australian Plague Locust outbreak
Spring locust situation
Why are we expecting a locust plague this spring?
In late autumn (April-May) 2010, large swarms of locusts were present in southern NSW, northern Victoria and south-eastern South Australia, with widespread egg laying evident at that time. Due to persistent favourable conditions, many female locusts were able to lay multiple batches of egg. These eggs will hatch in spring 2010 and are likely to cause significant crop and pasture damage unless effectively managed.
What regions are most at risk in spring?
In spring 2010, high-density locust hatchings are expected in parts of NSW, northern Victoria and eastern South Australia. The Australian Plague Locust Commission (APLC) has developed a map identifying key risk zones for anticipated locust activity. Some localised high density hatchings are also likely outside of these zones.
Will locusts still be present after spring?
Yes, locust swarms are likely to be present after spring. The locust control strategies used by the APLC and state agencies are designed for population and damage management, rather than locust eradication. When successfully applied, these kill about 60 per cent to 70 per cent of the total locust numbers by targeting the highest density infestations. Even with the control efforts of individual landholders, there will still be at least 20 per cent of the population left untreated. In seasons where numbers are moderate or low, this 20 per cent does not present a major problem. This spring, however, 20 per cent of the anticipated population will represent large numbers of locusts which will mature and swarm. These locusts are likely to breed and continue to damage crops and pastures, meaning that locust control may need to continue into summer.
Will the recent rainfall and flooding affect the locust infestation?
Recent rainfall and flooding are not expected to have a significant impact on the extent or intensity of the spring locust infestation. It may delay hatchings in some areas by one or two days, as water logged soils will remain slightly cooler, slowing egg development.
How can I get the latest information on locusts and locust control in my area?
For the latest information on locusts and locust control in your area, contact your relevant state agency. Contact information for each agency is available on the APLC website or in the Grains Research Development Corporation’s Plague Locust Control Fact Sheet. You can check the predicted hatching dates for your region on the APLC’s current situation webpage.
Landholder crop and pasture protection
How can I assess when locusts are likely to hatch on my property?
The APLC will continue to revise the hatching dates based on the actual air and soil temperatures leading into early spring. Check the predicted hatching dates for your area on the APLC’s current situation webpage.
When should I start surveillance on my property?
You need to start surveillance on your property at least two weeks before forecasted hatching dates. Predicted hatching dates are available on the APLC’s current situation webpage. Focus on areas where swarm or egg laying activity was evident in autumn, as well as headland, roadside and track areas. If you find hatching locusts, revisit this area frequently (preferably daily) over the following three weeks to determine when hatching is complete. This will provide a clear indication of when it is most effective to spray on your property.
How can I report locust hatchings and outbreaks?
You need to report locust hatchings and swarms to your local state agency. In NSW, reports need to be made to the Livestock Health and Pest Authority (LHPA). In South Australia, Victoria and Queensland, reports need to be made to the state agencies. Contact information for each agency is available on the APLC’s information for landholders webpage or in the Plague Locust Control Fact Sheet. You can also report locust activity to the APLC on 1800 635 962 or via the webpage.
What insecticides should I consider?
The only way to control hatched locusts is with the application of registered or permitted insecticide. The Plague Locust Control Fact Sheet includes tables of all insecticides registered in each state for locust control in different crops (cereals, oilseeds, pulses and pastures). These tables include information on withholding periods and grazing intervals to be observed after pesticide application. Contact your chemical supplier as soon as possible to avoid delays in supply.
How can I ensure that enough of the right pesticide is available when I need it?
Determine what chemicals you need and contact your chemical supplier well before the expected hatching dates in your area. If locusts were evident on your property in autumn, you should consider having sufficient chemicals available to treat up to 20 per cent of your property, although this requirement will vary considerably between properties.
When is the best time to spray?
You can minimise locust damage to your crops and pastures by targeting hoppers (the period after the eggs hatch and before the juvenile locusts are able to fly). The most efficient control can usually be achieved by spraying around 2 weeks after hatching, as this is when hoppers will be at their highest density. Locust nymphs are in much higher density than adult swarms, so you would need to cover a much larger area if you don’t target nymphs. Only use registered or permitted insecticides. Always follow the instructions and observe any restrictions on the label. Check for off-target impacts, such as nearby livestock, bees, aquaculture, organic production, dams and waterways, before undertaking any spraying. The Plague Locust Control Fact Sheet provides further information on using insecticides.
Is it worth spraying adult locusts that have infested crops?
The best results come from targeting hoppers (locust nymphs), not adult locusts. Adult locusts are far more mobile than hoppers and are therefore more difficult to target especially with ground spraying equipment. In addition, locust control insecticides only affect the locusts to which they are applied and do not provide any residual protection from adults flying into an area later. As a result, it can be very difficult, time consuming and expensive to protect crops and pastures from adult locusts.
How can I minimise the risk to bees?
Even if you don’t have hives on your land, bees may forage in areas you intend to spray. Before spraying, it’s important that you speak with your neighbours and any local beekeepers and arrange for nearby hives to be moved to areas where locust control is not expected. Some insecticides remain active for up to 28 days from application. It’s important to plan ahead for the relocation of bees as decisions to spray are sometimes made quickly. You should always follow pesticide label directions or permits for buffer distances or exclusions for water courses, water bodies, bee hives and other restricted areas. More information minimising off-target risks is available in the Plague Locust Control Fact Sheet.
Will I still have to spray locusts if the APLC or the state agency undertakes aerial spraying?
There are many areas on properties that the APLC or state agencies cannot access, particularly when undertaking aerial control which is subject to strict buffer distance restrictions. To implement the most effective locust control possible, you will need to undertake ground control to cover the areas where agencies could not implement control.
How will I know if the APLC has sprayed my property?
The APLC will gain your permission before spraying on your property. An APLC representative will run through a checklist of possible hazards on your property. They will inform you of the type of insecticide to be used and any withholding periods that may apply. Even if your permission to spray is obtained, it does not automatically mean spraying will take place on your property. If spraying does occur you will be provided with a map showing the area sprayed and the details of the insecticide used.
Managing chemical residues
What is a harvest withholding period (WHP)?
Every insecticide has a harvest withholding period (WHP). The WHP refers to the time that must elapse between application of a pesticide and harvest, or cutting (windrowing) for harvest, of grain or seed crops. The WHP ensures that residues in harvested products do not exceed set levels. You must observe the WHP specified on the product label. More information on WHPs is available in the Plague Locust Control Fact Sheet.
Why are WHPs important?
There are significant risks for not observing the WHP for grain, hay, pastures, meat, milk or any other production. Not observing this requirement contravenes legislation, and may result in the harvested product being unsaleable at significant cost to the landholder, due to residue levels higher than legal standards. More information on WHPs is available in the Plague Locust Control Fact Sheet.
What are export slaughter and grazing intervals?
The Export Slaughter Interval is the minimum period that livestock must be put on to clean pasture or feed before slaughter. The Export Grazing Interval is the minimum period that must elapse between the application of a chemical, and slaughter of the stock where grazing has continued on the treated crop/pasture from the time that the chemical was applied. SAFEMEAT and the Australian Pesticides and Veterinary Medicines Authority (APVMA) have recently produced an information sheet to help answer common questions on the management of residues following plague locust control. This document is available from both the APVMA and SAFEMEAT websites. The SAFEMEAT Plague locusts, wingless grasshoppers and livestock residues brochure should also be consulted for managing residues in livestock.
APLC’s role
What role will the APLC play this spring?
The APLC manages locust populations that pose a threat to agriculture in more than one member state—Queensland, NSW, Victoria and South Australia. In spring 2010, the APLC will focus control efforts in western and southern NSW and north-western Victoria. Areas of south-western Queensland and north-eastern South Australia may also require treatment by the APLC. This will be determined by post-hatching surveillance.
How does the APLC define its priority for control activity?
The APLC’s role is to monitor and manage locust populations that pose a threat to agriculture in more than one member state—Queensland, NSW, Victoria and South Australia. The APLC will therefore assess whether the situation represents a multi-state threat, and where strategic control will contribute to managing the current and ongoing locust threat. Control activity by the APLC and state agencies is designed to complement and not replace locust control by landholders. As all APLC locust control is by aerial treatment, operational efficiency will also dictate that priority is given to larger and more open areas, leaving smaller areas to ground control by others.
Why does the APLC wait so long after hatching to implement control?
Targets suitable for aerial treatment are not evident until they start to aggregate and form dense bands of hoppers. There is also a threshold of infestation that determines the economic viability of aerial spray operations.
Will the APLC and the state agencies have all spray aircraft tied up for locust control?
The APLC and state agencies have been working with aircraft operators for several months to ensure that aircraft and pilots will be available for locust control operations. Each agency has a panel of accredited operators, but there are many other operators not engaged by the agencies. Even those operators engaged by the APLC and state agencies will have some capacity for other operations. Contact your preferred aircraft operator as soon as possible and discuss your possible needs for spring.
Environmental management
What buffers does the APLC use around dwellings, dams, watercourses and other restrictions?
When applying chemical pesticides, the APLC uses a ‘no spray’ buffer of 1.5 km between sprayed areas and any sensitive area downwind such as dwellings, dams and waterways. Similar buffers are also applied to any environmentally-sensitive areas. The APLC also avoids the use of pesticides for five kilometres all round bee hives.
What locust control is planned for public lands, including national parks?
Plans for locust control on national parks and other public land areas have been negotiated with the appropriate state agencies. In some cases, this may also involve activity by local government authorities, particularly for roadside areas. In national parks or other conservation areas, the biopesticide Green Guard ® is planned to be used. In all areas of public lands, appropriate controls will be put in place (including buffers as required) to ensure public health and safety.
Where and how can Green Guard be used?
Green Guard ® is an environmentally friendly control for locusts. It uses Metarhizium—a naturally occurring fungus that will infect and kill locusts. It has full registration with the APVMA and is available through chemical resellers and, in NSW, through your LHPA. Before use, organic growers should check with their certifying body to ensure that the specific formulation and carrier oil are accredited organic inputs.
Will the APLC still spray locusts on certified organic farms?
The APLC uses the biopesticide Green Guard ® on certified organic farms and environmentally-sensitive areas such as national parks. The APLC will always gain your permission before undertaking any spraying. Through this contact, the APLC will identify organic properties where control is to be implemented or adjacent to these properties. If the APLC is undertaking locust control on a property adjacent to a certified organic property, it will only use Green Guard ® within 1.5 kilometres of the organic property.
What effect do the locust pesticides have on the environment and wildlife?
The APLC only uses insecticides which are registered by the APVMA. Part of this registration process requires an assessment of the off-target environmental impact and human health and safety, as well as residues. The APLC applies additional safeguards to minimise any off-target impact. For example, the APLC applies significant buffer zones to areas of particular environmental sensitivity, such as habitats of rare and threatened species. In these situations, the APLC will use the biopesticide Green Guard ® which is made from the naturally occurring Metarhizium fungus. This fungus is quite specific in its target range, and so can be used for locust control in national parks and other similar areas. When using the insecticide Fipronil, the APLC applies this product in discreet strips leaving up to 95 per cent of the control area untreated. These strips are placed in a way that uses the natural ‘marching’ habit of high density locust nymphs who move rapidly over long distances, thereby exposing themselves to this pesticide. The APLC has developed this technique so that there are large untreated areas which act as refuges for non-target insects and organisms that rapidly recolonise the treated strips.
Further questions not covered in this list
Email your question to the APLC and if we think it would be a useful addition to this document, we'll add it in the next day or so.
20 Sep 2010