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Contours Winter 2008 html
Contours podcast - Contours Winter 2008 Locust podcast html version
Transcript of interview between the Director of the Australian Plague Locust Commission Chris Adriaansen and DAFF Online Editor Selina Mitchell.
Selina Mitchell: Hello and welcome to Contours, I’m Selina Mitchell. Locusts are a growing problem for Australian Agriculture. Modern land cultivation is giving them the perfect environment to breed, and feed. Chris Adriaansen is the Director of the Plague Locust Commission which monitors and controls this ferocious pest. I asked him to describe the difference between a grasshopper and the more problematic locust.
Chris Adriaansen: Probably the main difference between locusts and grasshoppers is in the way that they act around one and other. Grasshoppers are normally solitary creatures, they don’t gather together in large numbers, they don’t form swarms, whereas locusts, once they get to a certain population density will form swarms that people most commonly associate with locusts. The other thing about locusts is that when they hatch out of the ground the nymphs do actually stay together for a period of time and its those marching nymph bands that also result in fairly significant damage to crops and pastures because they form a front and then just march through country and take out the vegetation on the way.
Selina Mitchell: So is it those characteristics that make them such a formidable pest? What else about locusts makes them so difficult to control and manage?
Chris Adriaansen: The fact that they do aggregate into such large numbers at times is what really makes them the pest species that they are. We have obviously had locusts in Australia, different species, for many many years, they’ve been here since certainly before white settlement, but we’ve seen significant changes in land use patterns etc that have provided conditions for locusts to actually build up in much larger numbers on occasions. What we also see is that locusts because they do gather in such large numbers will take out very large areas of vegetation as they move through a piece of country. The other thing about locusts as opposed to grasshoppers is that locusts can move very, very large distances within short time periods, locusts will move during the day and you will see swarms moving during the day and people often report swarms or small numbers of locusts hitting the windscreens of cars etc. However their major movement actually occurs at night where given the right weather conditions and wind patterns they can move at some fairly elevated levels, about 500 to 1500 metres above the ground level and they’ll use wind currents to move anything up to 700 km in one night. So this is one of the problems that we have with locusts is that they can be here today and gone tomorrow and it makes the challenge of controlling them all that more difficult.
Selina Mitchell: How do you control them and how do you monitor them?
Chris Adriaansen: We do a fair bit of physical surveillance to actually look for locusts on the ground. We then also combine that with other information that we gather with regards to land condition and weather patterns. So we use Bureau of Meteorology information to be able to look at where the wind patterns might be taking locusts as they migrate from one area to another, where they are more likely to reside because of land conditions, so we’ll use land sat (satellite) mapping to look at land condition to be able to then have an idea of where to target our surveillance. We started to also use some more innovative technology in the form of insect monitoring radar, and this is a project we’re working on with the Australian Defence Force Academy where we have some specifically constructed radars positioned—we have two at the moment in Western Queensland and Western New South Wales—where we’re using that radar to actually look for the large migratory flights of the adult swarms overnight. So because of that flight distance where they can travel 500 to 1500 metres above ground level the radar is actually able to pick up where we have large numbers of locusts moving and it’s also able to provide us with information about where they have come from and where they’re headed towards. In terms of control it’s the same old story: early and often. So our best efforts are with the collaboration of individual land holders and also the state agencies to implement controls at the early stages of locust development. We use a range of different control techniques. We make extensive use of a bio pesticide that’s commonly sold as Green Guard, it’s the Metarhizium fungus. It is a specific fungus that attacks locusts and related species and doesn’t have any impact on other native insect species or other flora or fauna, so this Metarhizium fungus will when it’s applied will actually attack the locusts species and will take them out. It’s not a knockdown chemical so it does take a bit of time to work but in the end result we can apply that into sensitive areas and onto organic properties and places like that without any problem. In other cases where we do have to use a chemical pesticide we’ve refined our techniques to such an extent that we use less then the equivalent of a Coke can of pesticide over three football fields. So we use very, very small amounts of pesticide. We don’t blanket spray country we apply it in bands so that we use the locust movement itself to assist in maximising exposure to the pesticide.
Selina Mitchell: Chris Adriaansen thank you very much for your time.
Chris Adriaansen: That’s a pleasure.