INSTITUTE, PUSA, FOR 1916-17 113 



•of worms becomes a source of disease for a much greater 

 number and for this reason alone would require suppres- 

 sion. 



Infection once introduced into a rearing house is carried 

 on and spread through the agency of dust, human beings, 

 and insects, carrying the spores of the disease, not only 

 from one part to another part of the same house, bat almost 

 certainly to other houses in the same neighbourhood. 

 Similarly the spores may be spread through widely separ- 

 ated areas to a lesser distance by wind, but to unlimited 

 ones by infected material such as cocoons and seed eggs 

 sent by post, the latter material, although hereditarily free 

 from disease, possibly contaminated during examination. 

 My own observations in seed selection nurseries, lead me to 

 conclude that this is by no means an unlikely means of 

 spread of infection, aggravated in most instances by the 

 faulty technique of examination which results in the 

 accumulation of infective material in the selection build- 

 ings. 



The persistence of infection in a rearing house will 

 depend upon several factors about which at present very 

 little is known, but as to which further information must 

 be obtained if any success is to attend the efforts of rearers 

 to avoid losses by diminishing the sources of infection. 

 Nothing is known in India as to the action of the various 

 antiseptics, such as copper sulphate, at present occasionally 

 used for the disinfection of rearing houses. It has been 

 assumed that they are efficacious, but so far as I have been 

 able to ascertain this assumption is based, like the examin- 

 ation of moths, upon another one, that what is good in 

 Europe is good in India; there is more reason indeed for 

 assumption in the case of antiseptics than there was for 

 the other one connected with seed selection, but it would 

 seem highly desirable to test the efficacy of such antiseptics 

 as are available and reasonably cheap, by actual experi- 

 ment. Owing to exigencies of other work I have been 

 obliged to confine experiment during the past season to 

 another, and what appeared to me to be a more important 

 : point, namely, the viability or persistence of infective power 



