IV. A NOTE ON DISEASES OP THE ERI WORM (ATTACUS 



RICINI). 



During my investigations, the Eri worm seems to have been 

 singularly free from disease. I received no notice of any diseases 

 having broken out among them, and my enquiries made to the 

 Assam Sericultural Department have always resulted in the infor- 

 mation that the worms were in good condition and showing little 

 disease. The eri worm has been studied in some considerable 

 detail by Lefroy and Ghosh (1912) during an extended experiment 

 at Pusa, so that I have felt there was little to be gained by going 

 over the same ground again. In the report published by these 

 workers and in Basu's (1915) report a great deal of useful informa- 

 tion will be found. I wish here just to make a few remarks on 

 their findings regarding disease. 



Parasitic diseases are got but with the exception of the " fly " 

 pest, which seems to take a heavy toll in Assam, they do not seem 

 to cause the rearers much trouble. Muscardine and pebrine were 

 both got but they are not factors of much importance. I cannot 

 agree, however, with the opinion of Lefroy and Ghosh (1912) that 

 the absence of actual disease (pebrine) makes the examination of 

 moths unnecessary. Nosema bombycis is a parasite of the eri 

 worm, and while it may not cause disease it ought to be eliminated 

 as far as possible. In Basu's report it is stated that an experiment 

 in rearing eri worms on a large scale at Kamrup in 1886 by the 

 Deputy Commissioner came to a very untimely end through pebrine- 

 It is possible that the disease was not correctly diagnosed or that 

 pebrine was not the sole cause of the disaster — it would be rather 

 strange if this isolated epidemic of pebrine had occurred and no 

 other similar case was known — but be that as it may, every pre- 

 caution should be taken, and certainly in rearing seed cocoons in 

 Government establishments only examined seed should be used. 

 It would not be necessary to examine the seed issued to rearers,, 

 if the stock were kept sound. 



Just as in the case of the muga worm, it is the rot diseases that 

 seem to be of importance in the eri industry and here too it is 

 flacherie that causes the greatest loss — grasserie is said to be rela- 

 tively unimportant. The flacherie reported from the eri worm 

 would seem to be the same as that from the muga and mulberry 

 worms. In Lefroy and Ghosh's report it is said that the disease 

 was being investigated by the Imperial Agricultural Bacteriologist, 

 but as far as I know nothing was published on the subject. I 

 isolated the bacteria present on castor leaf and in the gut of a 



( 85 ) 



