Research On Improvement Of Methods Of Group Sampling Inspection For Pebrine Of Silkworm Eggs On Card

The pebrine was an infectious disease which silkworm was infected by Nosema bombycis Naegeli, it had a destructive harm to sericulture, and it was the only one of quarantine index for silkworm eggs quality. There was an important measure for prevented that disease which was carrying out pebrine inspection for silkworm eggs, and it was based on the inspection standard. The cocoon yield in Guangxi has been kept first in the whole country for six years in succession since2005. The silkworm F1hybrids in Guangxi were produced with the mode of eggs on card. There were some deficiencies for the actual industry standard and local standard, so it was necessary to establish a feasible inspection standard which based on the actual production of silkworm eggs in Guangxi.The theory of new plan was based on several principles such as probability theory, mathematical statistics, economics, management science and sampling inspection principle, and its basis mathematical model was adopting super geometry distribution and the two distributions. Its unit was group, the percentage of diseased moths was transformed into unqualified rate of group, new mathematical model was designed and come into being which was fit to pebrine inspection of mother moth. A new sampling inspection plan was form on the basis of characters of current standards.There were three indexes for theoretical analysis such as the sampling inspections curve (OC curve), average sample number curve (ASN) and opinion ratio (OR). The results showed that new plan could ensure the benefit of user, and the benefit of producer was reduced at the same time. The average sample number curve (ASN) of new plan was only67.28%and74.8%that of actual standard of silkworm eggs on card in the typical analysis of small batch and great batch, and their opinion ratio (OR) was1.985and1.196, respectively. Therefore, the discriminating rate of new plan was better than that of the actual industry standard.Three methods which included actual industry standard of loose eggs, actual standard of silkworm eggs on card and new plan were compared with228batches which were82087cases in all. The result showed that the percentage of qualified lot for inspection of new plan was61.73%which was31%more than that of actual industry standard, and14.23%letter than that of actual standard of silkworm eggs on card. The inspection group number of new plan was64.38%and66.67%than that of actual industry standard and actual standard of silkworm eggs on card, respectively.97.51%silkworm eggs which were qualified by inspection with actual industry standard were accepted with new plan, and45.85%silkworm eggs which were not qualified by inspection with actual industry standard but were accepted with new plan;81.26%silkworm eggs which were qualified by inspection with actual standard of silkworm eggs on card were accepted with new plan, but18.74%silkworm eggs were not accepted with new plan, and all unqualified silkworm eggs were not accepted with new plan.The theoretical analysis of new plan was similar to the actual comparison test. New plan was cleared up a question that it was not equal between unqualified groups and diseased moths. New plan was improving actual industry standard which was stricter and the risk of producer was increasing. New plan was improving actual standard of silkworm eggs on card which was lower and the risk of user was not control. The inspection result of new plan was exact, and its inspection sample book was little, so it was provided accuracy and economy. Therefore, the design of new plan was reasonable, its inspection result was authentic, and it was feasible.