REPORT ON THE DISEASES OF SILKWORMS IN INDIA 73 



Amount of the disease in India. While flacherie is respon- 

 sible for very heavy losses in European and in Japanese sericul- 

 tural establishments, it is not a very serious pest among multi- 

 voltine worms in India. In Kashmir when univoltine worms are 

 reared, it frequently causes serious loss, but in my tours in India 

 I have rarely seen many cases. In Appendix II it will be seen 

 that there are certain numbers of rearers who complain o£ 

 flacherie, but on the whole Mukerji's opinion that " in Bengal 

 flacherie is regarded as less injurious than pebrine, muscardine 

 and grasserie " is still correct. In the census results — Appendix I 

 — a large percentage of flacherie will frequently be found. It is 

 doubtful if these figures represent the true state of affairs however. 

 If bacteria are found in a moth on examination it has been put 

 down as flacherie. In many cases, however, the moths have died 

 previous to examination and the bacteria present are those nor- 

 mally found in dead moths — dead moths were frequently examined 

 in order to make records of pebrine as full as possible. The pre- 

 sence of large numbers of bacteria in a living moth may possibly 

 be an indication that the caterpillar had been attacked by flacherie 

 in a mild form and I have accepted that idea, but after all it is 

 flacherie in the worm that is the important thing, and if the death 

 of worms from this cause is not so common as death from other 

 diseases I do not think the rather high percentages found in some 

 of the examinations of moths need cause much alarm. I cannot 

 find any good evidence in favour of regarding flacherie as a herit- 

 able disease (Experiment 27 A). 



The common sources of infection. As I have tried to show 

 above, flacherie- cannot, strictly speaking, be called an infectious 

 disease. The French sericulturists maintain that it is infectious, 

 and the two bacteria which they claim to be the cause of flacherie 

 may persist in a rearing room from one year to the next and so 

 carry on the infection. We have seen, however, that the food of 

 the caterpillar constantly carries these bacteria, so that this must 

 be taken as the common source of the bacterial infection when it 

 is got. It is possible that the dust from an old rearing room may 

 cause flacherie, but this is probably to be explained by the diges- 

 tion being upset by the dust and the bacteria normally present in 

 the gut getting the opportunity to multiply to an abnormal extent. 

 If, however, the bacteria are regarded as being organisms of infec- 

 tion, we must look upon the food supply as the source of danger 

 rather than upon the dust which may be present in a rearing room 

 from the previous rearing. 



Methods of protecting the worms from disease. Even 

 those who allot the most important part I a this disease to the 



