The locust plague and its suppression / by Æneas Munro.

  • Munro, Aeneas.
Date:
[1899]
Catalogue details

Licence: Public Domain Mark

Credit: The locust plague and its suppression / by Æneas Munro. Source: Wellcome Collection.

    355/388 (page 331)
    an obstacle to the progress of the “army” is one if not the most used by all the Latin and Eastern races—in North and South Africa,, in Europe, in South America, in India, and in China. The Italian colonists use it largely in the Argentine, and it is common in South Africa—I have seen it in the neighbourhood of Johannesburg. Not- withstanding what is on p. , I am surprised that the people have not taken the trouble to examine what, history says, and says distinctly,, in regard to the experience of this method. In the first place, let me point out the want of unanimity in regard to the dimensions of the ditch or trench. Some advise 18 in. wide by i ft. deep, others 18 in. by 18 in., others 2 ft. wide by 18 in. deep, and others 2 ft. by 2 ft. And so on, according as the parties believe in the jumping capacities, of the “army” for which the trap is formed. But there is a funda- mental error underlying this method, and I do not wonder that it has failed under every age. The test of the success of the plan is not to be measured by the distance or height the insect can jump at this time, but by its power to climb. It, then, it can climb over a wall or run in any direction upon it, although 30 ft. high, why on a priori grounds should it not climb the side of a ditch or trench 2 ft. in height? So it has always done it, without an exception. I have never been able to discover the advantage of having recourse to this means—at all events pure and simple. It serves only as an impediment to the progress of the insects without a doubt, and when in the ditch or trench they may more easily be got at and killed or mangled. 841. The ditch should be about 2x2 ft., and if the locusts are travelling from the north towards the south, the south side should be as perpendicular as possible; .better still, if under-sloping, and certainly not slanting so as to render it easy for them to crawl or creep up. It can be easily perceived that if the soil is dry and hard it will cost a. considerable sum to make a ditch or trench of the kind. The point to be judged is, whether or not advantages proportioned with the cost, can be obtained from this method ? I am bound to say that, from what I have seen, the enlightened portion of farmers do not think so. There is something catching in the idea, but it is far from satisfactory. The usual plan is that when the hoppers fall into the trench, a man walks therein and kills them with a scourge. This goes on until the army thins away, or the ditch is filling up, or the stench is so bad that another has to be made and the earth thrown into the old one, and the locusts therein covered up and buried. 842. It is rather difficult and costly to make an under-sloping side,, and if made, the falling portions will require considerable attention and repairs. Therefore, while the “ under-sloping ” cut would be better, it will be found in practice, when this plan is decided on, that the perpendicular side will be that most expedient and adopted. There