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Thursday, 29 November 1973
Page: 4082

Mr WENTWORTH (Mackellar) - During October there were numerous reports in the newspapers of locust depredations. Those reports seem to have tailed off because the depredations, although still continuing, are in a phase of lull.

I do not believe that this is anything more than a temporary respite. I think the position is likely to become a good deal more serious next month. This is not inevitable; it depends upon the weather. But if the weather pursues its likely course, as far as one can foresee the locust plague which we will have next month and during the autumn will be the worst ever experienced in Australia. This has come about because of the quite unusual weather pattern - the succession of cold fronts which have come over from the west and which have brought to the centre of Australia and the western part of Queensland and New South Wales quite unaccustomed rain.

The potential seriousness of this situation should be realised. I know that the Government has done something in this regard. I acknowledge that it has made available, I think, defence auxiliaries costing about $60,000 and that it has offered, I think, $500,000 as a dollar for dollar subsidy to the States. But I am afraid that what the Government has done has been too late and will be too little in view of the quite extraordinary weather patterns which have established themselves during this year. The New South Wales Government, I think, has requested the establishment of an anti-locust commission, and I am hoping that this proposal will receive more sympathetic and energetic action from the Government than it has to date.

The position of the Commonwealth has been complicated by a tragic event, namely, the recent death of Dr Clark, who was the key man in the Commonwealth Scientific and Industrial Research Organisation in the locust campaign. I can realise, and we all would realise, that an event of that character must throw things out of gear to some extent. The Commonwealth, I think as long ago as 1964, embarked on an anti-locust investigation in the CSIRO and brought in advice from overseas, where for many years there has been an anti-locust establishment which more recently has been taken over by the United Nations.

Let me deal with the nature of the locusts. Our Australian plague locust, the Chortoicetes terminifera, is not the same as the plague locust of the Middle East, the Schistocerca gregaria; but it is a cousin and in many respects it behaves in a similar way. It is a little smaller, but it shares the peculiar manifestation of the phase change and it has the same capacity to migrate. The other locust in Australia, the Austracris guttulosa, what is known as the spur throated locust, is more likely to give trouble in the north, but it can still make some incursion at least into the northern part of New South Wales.

The important point to remember about our plague locusts is what is known as the phase change. In the solitary phase these insects do not breed very extensively, but when their concentration gets to a certain level a population explosion occurs and the solitary locust undergoes morphological and other changes and becomes the plague locust operating in bands and behaving in quite a different way. This apparently is a behaviour common to all related locusts in various parts of the world. This phase change, which was not recognised by scientists, I think, until as late as 1920 or thereabouts, is the specific thing which makes the locust so dangerous. As honourable members know the locust breeds in this manner: The eggs are laid, the hoppers emerge and then they become winged. It is only in the gregarious state after the phase change that they form the locust bands. The cycle from egg laying to egg laying can be as short as 10 weeks, but it can be as long as 6 months or even 9 months, depending upon the weather.

Our locust migrates. The low flying swarms which we see seldom travel more than 10 miles in a day; but night flights, which recently have been tracked by radar and other means, are possible, and a night flight of a swarm can be as long as 250 miles in a single night. So the fact that they are distant is not always a protection. Much depends on the wind, and the breeding depends on the temperature and the rainfall. The meteorological conditions are controlling it. For example, the locusts which presently are operating in the Murray Valley and thereabouts are believed to have originated in a swarm at Blackall in Queensland and to have come south over approximately 9 months, with 3 generations breeding on the way and, of course, with an increase in each generation. Normally, the chief breeding grounds on the western plains of New South Wales and the Darling Downs spill their locusts westward with the wind, and the locusts die out in the western area because the ground is too dry and the conditions necessary for their multiplication do not exist. But this year the swarms, instead of dying out, are likely to have laid their eggs. The cold fronts which have come through precipitate the egg laying phase. This is why the danger of a further outbreak is now so near to us.

Let me mention the chief things that are threatened. The wheat probably will be in before any big plague develops. The plague is not inevitable, but it is highly likely. It depends on the weather. The chief victim would be the cotton in the Narrabri-Wee Waa area. Already the locusts are eating the cotton in the St George area in Queensland. Also threatened would be the fruit and vegetables in the Riverina and all coarse grains and vegetable crops which might be out at the time. We need more resources to combat the locusts. The cotton crop alone, which could be wiped out entirely, would be worth $25m or $30m in the Wee Waa area. I emphasise to the House that, although the danger is not inevitable, the potential danger exists at the moment and we should be doing much more about it. More resources are needed. Control cannot be exercised locally. We need to know more about what is happening. This morning I received a letter from the CSIRO which states that it has received no reports about the Birdsville area since last May. That letter states:

A high density locust population occurred at Birdsville, but no actual swarm developed. However, single swarms were reported from Glengyle and Monkira Stations, and a hopper band was located 40 miles north of Birdsville itself.

The letter further states:

No information is available on whether these locusts produced extensive egg beds.

It is not only this year about which we should be concerned. If the weather continues in its present cycle, the position might be even worse next year. We should do much more about it, particularly about surveys at the present moment. I believe that this is something which both sides of the House will support. I am not trying excessively to blame the Government. I think it could have done more, in view of the developing weather and the developing pattern. It has been slow to react. In the interests of the whole agricultural community of Australia, I think we should be devoting many more resources, both in the CSIRO and in other places, to this potential, not actual, menace which could be one of the worst disasters that Australian agriculture has yet experienced.

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