REPORT ON THE DISEASES OF SILKWORMS IN INDIA 59 



spore pushing out a delicate filament which penetrates into the body 

 of the worm, often through the spiracles. The filaments which 

 gain an entrance into the caterpillar body grow with great rapidity 

 and form a branching " mycelium " which ramifies all through the 

 body of the worm, drawing its nourishment from the living tissues, 

 especially the fat bodyX The filaments produce club-like swellings 

 or " conidia " which in turn give rise to fresh filaments or mycelia. 

 The body of the caterpillar thus becomes penetrated in all directions 

 with the fungus. The blood becomes scanty in amount and very 

 acid in its reaction, as are all parts of the body including the usually 

 very alkaline gut, and death of the caterpillar or pupa is rapidly 

 brought about. When the caterpillar is dead, the fungus pushes 

 its spore-producing branches through the skin, and the outside of 

 the diseased body thus becomes covered with a felt of white filaments 

 which give rise to countless spores. For the fungus to develop 

 from the spore to the final stage of spore production and the attendant 

 death of the worm attacked takes in Europe, and in India during 

 the cold weather, about ten days, in hot weather in India the course 

 is much more rapid, only about four days being required for the 

 complete cycle. 



A worm that has died from muscardine frequently shows some 

 little time after death a very characteristic production of crystals 

 on the outside of the body. These are said to be ammonium mag- ' 

 nesium oxalate and are large and prominent. 



It is to be noted that muscardine , like pebrine, is a. disease found 

 commonly in other insects, especially caterpillars. In other words, 

 Botrytis, like Nosema, is a common insect parasite and has doubt- 

 less been associated with the silkworm since its wild days. It is 

 not a disease which has attacked the caterpillar recently and 

 because of its domestication, although undoubtedly the conditions 

 of domestication have made the disease much more serious than 

 it is among wild insects. 



Amount of the disease in India and loss caused by it. 



As will be seen from Appendix II, the rearers in Bengal attribute 

 considerable loss to muscardine. During the first part of my 

 census examination (Appendix I) no muscardine was found, and 

 in the. course of our tours through the silk districts muscardine was 

 at first hardly at all in evidence. In May a very few^ases were 

 found in Kashmir. In September, however, my second assistant 

 found a great deal of muscardine in Bengal, and my census results 

 in this bund show total losses from this disease. As a certain 

 temperature and humidity combination is required for the propa- 

 gation of this disease, this seasonal occurrence was to be expected. 

 Muscardine is a disease that is peculiarly dependent on weather 



