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.

    375/388 (page 351)
    later. The work and experiments . . . enabled us, in the first instance, to prepare the fungus in such a manner, as regards purity and quantity, •as admitted of its being made use of on a considerable scale in the field. Since then I have endeavoured to find on what medium it can grow with greatest celerity, and in what manner it can be transmitted to great distances for use in the field. So far I have preferred the use of a saccharine agar whose reaction is faintly acid. Small tubes containing such medium are inoculated, plugged with cotton-wool, and incubated up to the moment at which visible growth is to be recognised by the naked eye. As soon as this occurs, the plugged end is immersed in liquefied hard paraffin, and when cooled such tubes are ready for transmission to distant parts. 884. Tube to be either broken on the ground or placed in a tank along with locusts.—“ For the purpose of affecting an area it suffices to break such a tube on the ground, either in high grass or in a suitable shade. It is, however, of the first importance to have a certain amount of moisture present, and hence its use is always most likely to be successful after rain. It is not advisable to use it after a drought, unless the place where it is deposited is kept damp. Various persons who have used it prefer to break a tube in water and to place some living locusts therein, which are subsequently released among a swarm. In Buluwayo the authorities are highly pleased with the success which has attended its use, but they insist on the greater advantage which follows if it is used during the voetganger stage. 885. Parts where transmitted. — “ Quantities of the fungus have been sent to various parts of South Africa, to North America, the United States, India, Australia, and to Buenos Ayres. In various parts where it has been used, most successful results have followed. 886. The fungus is that of the “ Empusa grylli.”—“ I regret that, owing to the urgent nature of the work in other departments, time has not admitted of the full study of its life-history, which I am desirous of having made, the more especially since its growth on artificial media gives such results as render the question of a symbiosis, as occurring in its life-history, deserving of some attention. It is, however, probable that the fungus is the Empusa grylh of the Entomophthorea, a group of fungi which for the most part live on or in the bodies of insects—into the cavities of the bodies of which they usually penetrate during life. After penetrating into the body cavity, they develop hyphse, or filaments on branches of which are borne gonidio- phores, e.g., carriers of brood cells. These hyphse penetrate from within outwards the body of the insect after death, and upon the outer surface the final stages of development are completed. The Entomophthorea do not live exclusively on insects. One species,