Danger in Laying Poison
By ALEC H. CHISHOLM
It may be true that there is a silver lining to every cloud, but It would be difficult to convince a farmer of this in relation to the cloud of grasshoppers now blighting many parts of Australia. Perhaps, however, all those millions of insects will not have lived in vain if their sudden uprising awakens Australians to a knowledge of how little is known of visitations of this kind. An entomologist said yesterday that Australia was the most backward country in the world in the study of insects and the knowledge of repressive measures. Possibly he meant that this was the most backward of the large agricultural countries. At any rate his remark merits attention.
Where did the grasshopper hordes come from? What has caused them to appear suddenly in such vast and menacing numbers? Men in the cities are asking these questions. They seem to think that answers should be well within the power of scientists. It is doubtful, however, whether anyone can do more than hazard guesses on the subject. Economic entomology is in its infancy in Australia, and little research among grasshoppers has been made. One suggestion is that the insects are apt to increase when large areas of land are cleared but left untilled. Another suggestion is that some unknown factor in a particular season promotes irruptions of grasshoppers. Actually scientists know little more of the subject than does the man in the street. Nor does it seem likely that they will know more until something in the nature of a bureau of biological survey is established. This will need to be an Australian-wide institution, since grasshoppers and kindred pests are not respecters of State boundaries. In the present plague the hordes seem to have arisen at various points in Queensland and New South Wales, and then, in one great mass, to have converged upon Victoria.
Medical scientists engaged in the fight against cancer say that if they could discover the cause of the disease they would be in a far better position to discover a cure. The same holds good in problems of economic entomology such as the one under notice. If Australia had a properly equipped biological bureau it should be possible to anticipate such visitations and perhaps to guard against them. Moreover, if prevention partially failed the knowledge gained doubtless would help toward a cure. At present the fight against the grasshoppers is largely experimental - a matter of striking blows at random. The firing of straw is effective up to a point. This used to be practised in some parts when hosts of grasshoppers in the flightless stage were seen. Another method being adopted in some parts, the use of poison baits, may do more harm than good.
When poison was laid for grasshoppers in another State some years ago the most striking result was the killing of a large number of insectivorous birds. Within a few days either the poisoned balts or the poisoned grasshoppers killed approximately 1,000 magpies and crows, and about 100 plain turkeys. There is, it would seem, a grave danger of this tragedy being repeated in Victoria if poison is broadcast.
Indeed it seems probable that the indiscriminate destruction of bustards (plain turkeys) in the west of Queensland and New South Wales has promoted the grasshopper plague, and it seems equally probable that some other plague will arise if many more birds are killed by poison laid for grasshoppers. It may be added that there are more than 100 different kinds of grasshoppers native to Australia, but only two or three kinds become serious pests. Grasshoppers are identical with the locusts of biblical fame, but the term "locusts" is often erroneously applied to those drummers of the trees, the cicadas.
FIGHTING GRASSHOPPER PLAGUE. (1934, November 9). The Argus (Melbourne, Vic. : 1848-1954), p. 3. Retrieved November 17, 2010, from http://nla.gov.au/nla.news-article10992479
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