Vol. XXVIl. 



IQ[0 



1 McAlpixe, The Romance of Plant Patholos^y. 133 



be a JMucor, one of the common bread-moulds, and this was 

 afterwards sup])orted by Massee, of Kew. The interest of this 

 determination hes in the fact that the true locust fungus is not 

 a Mucor at all, and the wrong one was sent out by mistake. 

 How it came about was this : The parasitic fungus which killed 

 the locusts was Empusa grylli, but Mucor was also present on 

 the dead locusts, and so, by an unfortunate mistake, the locust 

 fungus, which was sent out in tubes with gelatine, was a species 

 of Mucor, or a mould which is not a parasite. The locust de- 

 stroyer will only grow on the living tissues of the locust, and has 

 never been cultivated on dead substances. It is closely related 

 to the parasite on the common house-fly {Empusa imiscce). 

 Everyone is familiar with the dead fl}' stuck to the window-pane 

 and a white halo surrounding its body. 



In view of this scientific, although unintentional blunder, it 

 is interesting as w^ell as amusing to read of the wonderful success 

 of the imaginary parasite, reminding one of the effects pro- 

 duced by the bread pill or the coloured water of the physician. 

 In the annual report of the Government Entomologist for 1902 

 it is stated that " the locust fungus introduced from the Cape 

 has proved very successful against grasshoppers, especially in 

 the cooler and more mountainous parts of our State, no less than 

 400 applications for the fungus having been made by graziers 

 and others." In the report for 1903, the demand for the tubes 

 is shown to be largely on the increase, as it is remarked that 

 " the grasshopper fungus has been a greater success than we 

 anticipated, the applications for supphes numbering 1,207, ^^^^ 

 number of tubes posted being nearly 5,000." Mr. French 

 suggested that a small charge should be made for the material, 

 and this seems to have damped the ardour of those using it, for 

 in the report for 1904 it is stated that " the grasshopper fungus 

 tests have been followed up, and my suggestion as to making a 

 small charge for the material has made a large difference in the 

 number of tubes applied for, the number of tubes sent out 

 during the year being 842, and the amount received for same 

 r^y6 6s." 



It will naturally occur to you that if this " South African 

 locust fungus " has maintained its reputation as a locust de- 

 stroyer it will be extensively used in the country of its origin, 

 where locusts have caused such enormous losses ; but the report 

 of the chief locust officer has recently been issued in the Agri- 

 cultural Journal of the Cape of Good Hope for February, 1910, 

 and there is no mention of the locust fungus. He points out 

 that the most successful method of destruction is to spray the 

 veldt with a dilute solution of sodium arsenite and treacle, or, 

 if the grass is too short, to soak in this solution finely chopped 

 green vegetation, bran, or even the young locusts themselves. 



