Theoretical consideration was made to make an economical and rational method of samplinginspection for pébrine control by making use of the characteristic of early eclosion of silkworm moths diseased with pébrine of a lot, and the description was made on the five factors of investigations which are considered to be indispensable and sufficient for establishing a new sampling inspection method:-
1. Infection formula of pébrine disease.2. Relationship between eclosion dates and percentage of diseased moths of a lot.
In this item, there include experiments which are performed in all cases which have from the case of heavily infected moths with high, diseased percentage to the case of the very lightly infected, and in an unhealthy lot.
3. Comparison of descending grade of percentages of diseased moths among heavily to lightly infected moths accrding to the retardation of eclosion dates by the results of experiments 2.
4. Comparison between weights of healthy undried cocoon, its silk layer and those of the diseased respectively.
5. Investigation on the hereditary transportation of parasites into silkworm eggs.
5A. The case of hibernating eggs.
5B. Comparison between common acid treated eggs and those of the chilled and the acid treated.
In order to perform above experiments, it is necessary to make moths with various desired percentages of diseased ones infected with pébrine at ones discretion. Therefore, the results of experiment on the numerical infection of spores to a silkworm larva
per os which gave satisfactory answer were described. By this and the other correlated experiments, it became easy to obtain moths, apparently healthy despite infected with pébrine, and those with any desired disease percentages by oral infection at any instar.
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