PARASITIC FUNGI AND MOULDS. 



49 



have given rise to a surmise that if we could discover 

 the parasitic fungus of the phylloxera, we might 

 transform it into a powerful auxiliary of agriculture, 

 since by its aid the parasitic insect which 

 now ravages our vineyards might be 

 destroyed. 



From this point of view Giard 

 has observed several of these parasites 

 of insects, which he calls Entomo- 

 phthorece, from the name of their prin- 

 cipal genus, Entomophthora. Such is 

 E. rimosa, which attacks grasshop- 

 pers and the diptera of the genus 

 Chironomus, enveloping them in a thick 

 felt work formed by the winter spores, Fig. 23. Butterfly- 



nymph bearing 



and speedily killing them. In the 



same manner Isaria pulveracea attacks Pyrrhocoris 

 apterus, an insect which is often injurious to our 

 kitchen gardens. 



It has been asked whether Entomophthora Plan- 

 choni, the parasite of the aphis, might not also prey 

 upon the phylloxera, but the experiments made in 

 this direction have not hitherto been so successful as 

 to allow us to count on this means of averting the 

 scourge. With the same object, Hagen has suggested 

 the use of beer-yeast, which seems to have a destruc- 

 tive effect on insects, as it is developed in their tissues. 



