Cotton Seed Distributors - Web on Wednesday

Edward Joshua - Acting Protection Officer, DPI Dubbo - outlines the possible locust plague predicted for the spring.

Edward, we saw a large outbreak of plague locusts in the autumn in many areas of Queensland and New South Wales. What is the forecast for this coming spring?

The locusts that came through last autumn have laid eggs basically in the slopes and plains of NSW and they go from Goondiwindi in the north to Albury in the south and everywhere in between. There is a strong concentration of egg beds in central NSW. When daytime temperatures get up to 25ºC we will see those eggs start to hatch and we’re looking to that happening sometime mid September.

Obviously there’s been a lot of egg laying going on during the autumn from those swarms coming through. How can farmers and cotton growers get out and actually find those eggs?

There’s a number of good agronomic reasons for walking crops. What they need to do is take a shovel and go and dig in the soil 2 to 4 inches (25 to 50mm) down into the soil and physically look and see if they can find pods of eggs and then test those eggs to see whether they’ve got moisture inside them. If they have then those eggs are likely to be viable and if they find lots of them they’re likely to have bands this coming spring.

It sounds to me as if it could be as important as pupae busting across the cotton industry to actually get out and try and identify these egg beds and know they’re in the soil and just be prepared?

Yes, I think going out with a shovel, digging, finding where the swarms went, whether they did actually lay. A lot of locusts will test drill and not necessarily lay, so getting some information, finding out whether the eggs are in the soil on your land, are you likely to have a problem this coming spring? It’s good information to find out where they’re likely to be and then when the weather warms up a little bit you can go back to those spots where you have found eggs and look for the hatched hoppers and see if you can find bands which will need insecticide application to.

After hatching how long have you got before they need to be sprayed? What sort of window of application do we have?

Because of variations in soil temperature, hatching is probably going to take 10 to 14 days to happen. We’re looking to apply Fenitrothion 1000 EC by ground to the third and forth instar. In ideal conditions those instar stages will take 5 to 7 days for each stage, so we’re talking in the region of 3 to 4 weeks from hatching to control. So there is a reasonable window there; they’ll probably take somewhere in the order of 5 to 6 weeks before they fledge into adults where we’ve lost our opportunity for control, but if we can target at the third instar when they’re congregating into bands we can put a little bit of insecticide on a small area of the farm and control most of the locusts.

You mentioned Fenitrothion as a control agent. What other products will be available and where will farmers be able to get it from?

When landholders observe locust bands they should report them to their Rural Lands Protection Board. The Rural Lands Protection Board will provide them with Fenitrothion We do have some Greenguard®, it’s a fungus spray which can be used for organic growers. The Fenitrothion costs about $7 or $8 per litre. The Rural Lands Protection Board rates, the levee that’s put on noxious insects destruction, goes to pay for that Fenitrothion. If you go to Greenguard it’s about $37 or $38 a litre, so the additional cost over and above the Fenitrothion will have to be met by the landholder. Of course the application of the chemical needs to be met by the landholder as well.

Obviously in the spring we’re going to have winter cereals developing and then probably some early summer crops and obviously cotton in a lot of regions. What crops will be most susceptible to the swarms and then the adults as they move through?

The Australian Plague Locust, which is going to be the predominant species that we’re looking at are Australian natives and they prefer fine leaf native grasses, so they will go for those first. Then after that they will go for wider leaf crops, so certainly cereal crops. People will find them in all the winter cereal crops. Summer sorghum crops will be sown probably around 15 degrees soil temperature so we’ll see those emerging. Young cotton crops will also be susceptible and once bands congregate together and get in large numbers anything that’s green is likely to be eaten.

Moving onto more information for farmers, where will they be able to get more information on this topic?

Their first point of call should be their Rural Lands Protection Board rangers and the Rural Lands Protection Board. Secondly, I would go to the Australian Plague Locust Commission web page (www.affa.gov.au/aplc), which is a fount of information of all the entomologists who work on this. They also have a weekly update so you can get an eastern Australian perspective on what the locust situation is on a weekly basis from the APLC web page. The Department of Primary Industry web page also has a lot of information. If you need permits for garden style chemicals you can get them off our web page, there’s a lot of links to the APVMA so if you need registration. The other place where you can get information is msds.com.au where if you need safety information about the chemicals that you using it’s another good point of call. The other one to look at is Austlii (www.austlii.edu.au). The Austlii web page gives you copies of the latest copy of the legislation that you’re working under and this one we are looking at the Rural Lands Protection Board Act 1998 for NSW, the Occupational Health and Safety Act 2000, the Pesticides Act and the Protection of the Environment Operations Act 1997, so copies of those are available at Austlii.

Obviously applying this chemical the label would have to be adhered to and all the other regulations as far as spraying near waterways, towns, houses etc?

Yes all the buffer zones. People need to read the label, they need to read the MSDS, they also need to do their own risk assessment of the situation and observe all the rules and regulations that they would normally apply herbicides or any pesticide under, but document their risk assessment and there is a reasonable window for application, they can wait until conditions are prime for it and then record not only the conditions but also the forecast of likely weather so that if they’re going to go close on the edge of buffer zones they’ve got good information documented so that if something does go wrong they can prove that they were doing the best possible job with the best possible information.

With hatchings already noticed around Coonabarabran, what would be your final message to farmers as far as getting out there and finding out what’s in the soil?

Certainly go to where they observed locusts last autumn, dig in the ground with a shovel and find out whether they have eggs, walk their crops, have a look for locusts when they find them, report them to the Rural Lands Protection Board and access good information so that they can do the right thing, control the locusts and if everybody does a good job of that we hopefully won’t see the swarms that we saw develop last season.

Further Information:  Robert Eveleigh, John Marshall,  Craig McDonald or David Kelly