REPORT ON THE DISEASES OF SILKWORMS IN INDIA 67 



nary circumstances — only when the temperature was high. Thus- 

 their work would seem to show that under normal circumstances- 

 the organisms which are supposed to cause flacherie do not cause 

 this disease, but under abnormal conditions certain bacteria seem 

 to bring about the disease. 



Most of the work on flacherie has been done on univoltine worms, 

 so that it was necessary to test those different views on the multi- 

 voltine worms of India. In the first series of experiments (Experi- 

 ment 23) caterpillars were fed on juices from caterpillars that had 

 died showing symptoms of flacherie. In all cases the material fed 

 contained large numbers of the organisms typically associated with 

 flacherie. As will be seen, the death rate among these caterpillars 

 was fairly high, but in the majority of cases very few bacteria were 

 recovered although the dead worms showed symptoms very like 

 those described for flacherie in univoltine worms. The impression 

 got was that the growth of bacteria followed upon the serious 

 digestive disturbances induced by feeding the caterpillars on such 

 unsuitable, injurious substances. 



An outbreak of flacherie among the Muga worms in Assam 

 afforded an abundant supply of bacteria isolated from typical 

 cases of this disease. There were two organisms present in abund- 

 ance in the cultures made from the material collected. These I 

 have called Bacillus A and Micrococcus a. These were fed to 

 Nistari and Chhotapolu worms both in mixed cultures and in pure 

 cultures, and not a single case of flacherie fesulted (Experiment 

 24.) 



In Kashmir univoltine worms of French origin were found 

 suffering from typical flacherie. A variety of organisms were 

 isolated from these. All were bacteria that had already been 

 isolated from mulberry leaves, or the air, or healthy caterpillars 

 or diseased Muga worms. Some of these organisms, Bacillus A, 

 Bacillus G and Micrococcus a, were fed to Nistari worms 

 (Experiment 25, lots 9-12). One case of flacherie resulted in the 

 lot fed on Bacillus A grown under anaerobic conditions. 



Similarly, bacteria isolated from a moth which showed many 

 bacilli on examination, from mulberry leaves and healthy cater- 

 pillars were fed to normal caterpillars. In the lot of Nistari worms 

 fed on Bacillus B from the moth (lot 6) one caterpillar died showing 

 external symptoms of flacherie, but no bacteria were present in 

 the gut. Among the moths which resulted from these experi- 

 mental lots a few died shortly after emerging and one failed to 

 emerge — some of them showed bacteria, some did not. 



Thus under normal conditions multivoltine worms do not seem 

 to become infected with flacherie to any extent, even when they are 

 fed heavily on bacteria, some of which at least, as we shall see 



