436 Journal of Agriculture. [11 July, 1910. 



Agricultural Gazette of Neiu South Wales, p. 41, 1907. It is well known 

 in America and South Africa as producing disease and death among the 

 locusts there, and has also been found in Europe. 



As a locust destroyer, this fungus is of special interest, but only brief 

 reference will be made to the fungus itself. There is a well-known and 

 closely related example which is parasitic on the common hou.se fly and 

 known as Emfusa rnusccc. Every one is familiar with the dead fly stuck 

 to the window pane and a white halo round its body — the shroud which 

 has also been the cause of its death. The tubes or hvphas of the fungus 

 are inside the body of the locust, as shown in Fig. 15, and when they have 

 u.sed up all the nutrient material in the tissues, they project at the sur- 

 face and produce the pear-shaped conidia (Fig. 2). When the conidia are 

 ripe they are shot out as if from a pop-gun, and if they strike the body of 

 another locust they may infect it, and in this way the disease is spread. 

 These conidia are produced in countless myriads and scattered, so that the 

 fungus is not only widely distributed, but also rapidly reproduced. The 

 locusts have all disappeared during the winter months, and so the fungus 

 has to provide for a period of rest, which it does by means of the resting- 

 spores (Fig. 20). This fungus will only grow on the living tissues of the 

 locust, and has never been cultivated on dead substances. 



The " South African Locust Fungus," which is the same as the Aus- 

 tralian one, has attracted considerable attention, because it was at first 

 thought to be capable of being artificially cultivated and used for getting 

 rid of the destructive locust. But, by an unfortunate mistake, the locust 

 fungus which was sent out in tubes with gelatine was not that fungus at 

 all, but a species of Mucor or a mould which is not a parasite. The 

 parasitic fungus which killed the locusts was Empiisa grylli, but Muccr 

 was also present on the dead locusts and so it came to be mistaken for, 

 and cultivated and sent out as an insect destroyer which it really never 

 was. Cultures from the Cape were received by me in 1899 and determined 

 to be a Mucor as described and illustrated in the Agricultural Gazette of 

 New South Wales, p. 184, 1900. Now that we know the true state of 

 affairs that we have been importing the spurious article from the Cape, 

 while the genuine article was produced within our own borders, it behoves 

 us to .study the natural conditions under which epidemics of the locust 

 disease occur, and .see how far the true locust fungus can be utilized and 

 controlled by us. 



EXPL.^NATIOX OF PLATE. 



[Em-piisa grylli, Fres.) 



Fig. I. Locusts killed by the fungus... ... ... ... n.Tt. size 



Fig. 2. Conidiophores or conidia-bearers projecting from the junctions of 



the abdominal segments, two loose conidia above ... ... Xioo 



Figs. 3, 4, 5, 6. Successive stages in the development of conidia within the 

 conidiophore 



Fig. 7. Conidiophore after ejectment of conidium 



I'^ig. 8. Conidium on left forming a secondary conidium, upper half pro- 

 jecting 



Fig. I). Secondary conidium escaping from tiie mother-cell 



Fig. 10. Conidium beginning to germinate 



Ficrs. II, 12, 13, 14. Various stages in the development of secondarv coni- 

 diophores and conidia from a conidium. Culture in moist air... 



Fig. 15. Mycelium in abdominal cavity, showing commencement of aggre- 

 gation of contents in the formation of mvcelial bodies 



Fig. 16. Mvcelial bodies, two pale immature resting spores at right 



Figs. 17, 18, 19, 20. Successive stages in the development of resting 



spores from mycelial bodies ... ... ... ... X250 



