MICROBIAL DISEASES OF INSECTS 



909 



examined microscopically. If the moths did not contain the character- 

 istic microorganism, the strain they came from might unhesitatingly 

 be considered as suitable for seeding. The flacherie organism was as 

 easily recognized as the pebrine corpuscle, but the infection was more 

 difficult to prevent on account of the environmental conditions above 

 mentioned. 



Silkworms have been fed on mulberry leaves washed with water or 

 an aqueous solution of lysoform, but a few sporadic cases of flacherie 

 and emaciation occurred nevertheless.* 



Phototaxy has been employed successfully in selecting larvae of 

 Bombyx mori most resistant to flacherie. Newly hatched larvae 

 immediately turn to the source of light, while this movement diminishes 

 during the following days and disappears entirely at the end of the 

 first stage. During the subsequent stages there is an inverse but less 

 energetic movement and the larvae tend to avoid the light. The larvae 

 which are most resistant to flacherie are those which from the time of 

 their birth had travelled farthest, f 



THE "JAPANESE GIPSY-MOTH DISEASE' 



Streptococcus disparis n.sp. Glaser J 



HISTORY AND DISTRIBUTION. During the summer of 1915 a large 

 series of eggs of the Japanese gipsy moth (Porthetria dispar L.) were 

 hatched, which had been obtained for Glaser from Ogi, Japan. On 

 reaching the third stage many of the caterpillars began to die of a 

 peculiar disease which Glaser had never in previous years noticed in 

 any of his American cultures. The infection later spread to the Ameri- 

 can race, and the most vigorous methods of isolation and disinfection 

 had to be inaugurated in order to save most of the cultures from extinc- 

 tion. As the disease was very soon controlled, distinct in this respect 

 from wilt (polyhedral disease), a bacterial origin was at once suspected. 

 This disease was then studied in the belief that it might be used in 



*Sacchi, Rosa. Partial disinfection of mulberry leaves in feeding silkworms. 

 E.S.R. 39, pp. 560-561, 1918. 



fAcqua, C. The use of phototaxy in selecting from the moment of their birth 

 those larvte of Bombyx mori most resistant to the disease flacherie. E.S.R. 38, 

 p. 860, 1918. 



tGlaser, R. W. A new bacterial disease of gipsy-moth caterpillars. Jour. 

 Agr. Res. 13, 1918, pp. 5!5 



