THE LOCUST PLAGUE.

Hauraki Plains Gazette, Volume XXXVI, Issue 4813, 20 February 1925, Page 3

THE LOCUST PLAGUE.

INSECT WAR IN SOUTH INFORMATION OF THE PEST. During the last three years the whole of the Union of South Africa, but particularly the Transvaal, has been infested with swarms of locusts. There have always been these alarming visitations at more or less regular intervals. >he plague lasting for two or three years and then disappearing again for seven or eight years (writes a Transvaal correspondent of the “Manchester Guardian”),. A systematic spraying campaign is carried oftt; control pests also develop, which' eat the eggs, and birds feed on the matured insecta. Many flying swarms get blown out to sea. So the plague exhausts itself for a period. At present we are suffering from one of the worst visitations ever remembered. The Government is tackling the matter with energy and determination, but with hundreds of square miles' covered with the hopping insects the task sometimes seems beyond man’s powers.

The eggs are laid in sandy ground in little cases or pockets. These only hatch out after rain, but seem quite capable of waiting ten or twelve years for it without being in the least affected in vitality. Our present infestation is supposed to be due to heavy rains in the Kalahari three years ago. The locusts when they first come out are white and small. They turn black in a few hours, .and then closely resemble swarms of houisb-flies. At this stage they can only hop, and are known as voetgangers (“walkers”). They soon collect in swarms, and at night always sleep in thick clusters. This is the time to tackle them, for they remain in the hopping stage for six weeks or so, and once they reacn the flying stage very little can be done to destroy them. At present we are dealing with the voetgangers as hard as we can, the early September rains having - brought them out in countless millions.

The quickest and surest method of destruction is to lead them into long, dry grass and burn it. They are very easy to direct, the swarm generally t moving in a V-shaped column, and all following the leaders. If a small path in trig, grass is made ,in front of the leaders with a spade they will all hop down it, and can 'be directed wherever desired. It its a funny sight to see the myriads, of little fellows 'hopping past, but usually one is not in a- mood to appreciate it. The trouble of this method of destruction is that ,as the . locusts always hatch put after rain the veld is then green and riot easy to burn. Nor can it be followed on ploughed .lands or in. the sand among the rocks on the tops of the hills, both favourite breeding grounds. In these capes spraying with poison is the only remedy. A solution of arsenate of soda and sugar is used. Some are killed by direct contact with the poison, othefs by eating their fallen friends, and in this way the whole swarm killed off in about tlnee days.

This method, however, is not as simple as it soundp. The spraying has to be done at night, when the insects are massed together, or else in tiie very early morning; water is needed, for mixing the spray, while the voetgangers seem to delight in resting in inaccessible spots on the hilltops, where all the water has to be carried up by hand. The poison must also be mixed with great care ; if too ueak it is of no ! use, and if too strong it kills the stock grazing on that velc ■ afterwards. Then, again, during the six weeks of its life asi a voetganger the locust goes through five moults, and as it stops eating for twenty-four hours before moulting, it is essential to follow up each swarm and if it is going to die as a result of the spraying, and, if not, to spray it again.

All this work has to be done just when one is most anxious to get ahead with the ploughing and planting. Last year in the two months after’the first rains fell we destroyed over forty big swarms on our farm of 3000 acres alone, aiid this was not by any means one of the most heavily infested. Last year we suffered • from invasions of locusts from neighbours’ farms, but this year each farm is receiving closer attention from the locust officer. When he is satisfied that all the voetgangers on a farm are destroyed ne gives the farm a clean bill of health, and then if mor,e arrive from neighbouring lands they must be destroyed, but a bill may be presented for the cost. During these six weeks the locusts eat ravenously, *t is hard bn the owner of a field of young' 1 cotton or mealies into which they get, as the crop is simply wiped out before they can be destroyed. But it is in the flying, stage that they are such a terrible menace. During the summer, when there are plenty of crops about, they are more particular, and stick chiefly tb mealies, but towards winter, as they get hungrier, they eat everything—grass, cotton, young orange trees —all are cleared off in a few moments. It is the most awful sight to the poor farmer with a field of ripening mealies, just ready to form cobs, to see the thin brown smoke against the horizon which in half an hour turns into a dense mass like a great fog descending on him. His years work disappears in a few minutes, and the only possible retaliation is to catch the locusts in sacks as they mass to sleep, boil them down, dry them, and feed them to the horses and hens. When it is understood that every female can lay .at-least 300 eggs, and that there are about.three generations in each year, so that one female can give rise to over eight milliards in eighteen months, it will be be seen what a herculean task the Government is faced with in trying to eradicate the pests. Apart from manufacturing poison and pumps, all of which are supplied free, it carries out actual spraying on unoccupied farms. There are also locust officers allotted to every few square miles, reporting on swarms and seeing that they are destroyed. In addition to this a lot of

research is being done on the habits and breedimg-grounds of the locusts, and a big expedition has just returned from a .trek right through the Kalahari, the chief isource of the pest. The object of the expedition was to find the extent of the breeding there, to locate water available for spraying, to ascertain the best routes for lorries carrying poison, and to organise the natives and farmers for a campaign of destruction. Mr Malby, the chief Government entomologist, accompanied the expedition, and one of the officers of .the Air Force also went with it with a view to seeing if aeroplanes could be used effectively in the campaign.

Its report is not very cheering, though extremely valuable. It found about 20'0 square miles infested with eggs, and, of course, it did not by any means explore the whole Kalahari.