INSECT CONTROL 321 



trypanosomiasis, transmitted by tabanid flies, and as these 

 flies are preyed upon by a large wasp, Monedula Carolina, 

 in the South-eastern States of America, it was decided to 

 try the experiment of shipping the wasp pupae to Algeria, 

 in the hope that they would continue their beneficial work 

 in their North African home. Although the adults duly 

 emerged they do not appear to have flourished, at any rate 

 they have done little to control the tabanid flies. 



The second instance is that of the attempted introduc- 

 tion of the common American bumble bee, Bombus pennsyl- 

 vanicus, into the Philippine Islands. The red clover in 

 these islands was not a flourishing crop, owing to the fact 

 that there were no insects, properly equipped, for carrying 

 the pollen from flower to flower and so effecting fertilisa- 

 tion. For this reason the bumble bee was introduced, but, 

 despite the fact that the pupae were carried by hand by 

 Filipino students from the United States to the Philippines, 

 the attempt does not seem to have realised expectations. 



A second, and still more modern, method of natural insect 

 control is carried into effect by means of fungoid diseases 

 of insects. A few examples may be quoted with advantage. 

 As long ago as 1878, the larvae of some beetle pests of 

 wheat in Russia were observed to be badly infested with 

 a fungus, known to science as Metarrhizium anisoplice 

 and popularly named green muscardine. Since that time 

 green muscardine has been found practically all over the 

 world, and on all sorts and conditions of insects of widely 

 different families. Scientists discovered that the fungus 

 would thrive on a medium of boiled rice as readily as on its 

 insect hosts. Accordingly, in 1909, the fungus was culti- 

 vated on a large scale in Trinidad and used with good 

 effect against the " frog hoppers " which infested the sugar- 

 cane plantations and damaged the plants. Two methods 

 of spreading the fungus were adopted, according to the size 

 of plantation ; in both cases the spores of the fungus were 

 used. For the benefit of the unbotanical, it may be men- 



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