32 THE CULTURE OF THE MULBERRY SILKWORM. 



have died from calcino all the shelves should at once be cleaned and 

 divested of dead worms. The floor should be washed with a solution 

 of sulphate of copper (1 to 200 by weight), and a pound of sulphur 

 should be burned, or a strong wood smoke created in the room, which 

 should then be siuit u\) ti\e or six hours, after which the wonns should 

 be fed. Should any worms die the next day the beds should again 

 be changed and an ounce of sulphur ))unicd. The <iuantitv of sulphur 

 fumes that would kill rats, bats, and lizards and even human beings 

 does no harm to silkworms. No hesitation, therefore, need be felt in 

 fumigating the rearing room with sulphur; but eggs and thread nets 

 must not l)e subjected to sulphur fumes. Silkworms afl'ectcd with 

 calcino die before the moth stage; therefore, it is impossible for the 

 disease to be horeditai'v. But loose spores of the mold creating the dis- 

 ease may get on healthy eggs. These may be washed otf by a good 

 bath of fresh water. Some recommend a bath with a solution of sul- 

 phate of cop[)er (one-half \)or cent of co})per). In cases of calcino the 

 room should be disinfected immediately after the cocoons are gathered 

 and the paper and bi-ush used should be ))urned. 



As calcino is never due to infected eggs no attention novd be paid 

 to the presence of spores of the Botrytis in the microscopic examina- 

 tion to select eggs. 



GRASSERIE. 



Silkwoi'ms having this disease bcconu^ restless, bloated, and yellow. 

 If punctured they exude a pui'iUent matter full of minute polyhedral, 

 granular crystals. 



Grasserie is neither hereditary nor contagious. Unlike pel)i'ine, 



ilacherie, and calcino, it is not caused b}^ microbes capable of nudtiply- 



ing and creating plagues. Grasserie does little harm to silkworms in 



; , but in warm countries, as in Bengal, sometimes assumes an 



■'■ form. 



•'^af, and afterward on young leaf, are 

 ^^ large trees is the best means 

 o. 'w>f iu; -poradic appcxirance 



of grasseriv. the moltitig ])eriods. 



Feeding should noi ... ■ •■: - ' • bcguij uj 



molt, and should not be reconn... v;-l) out 



of the molt; otherwise they are likely lo iiuv. „ 

 often leads to Ilacherie, and when it occurs in uu e .. 

 indicates latent pebrine. 



o 



