• Journal of Sericultural and Entomological Science
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• v.32 no.1
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• pp.31-37
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• 1990

For fine-denier cocoon filament production, the precocious trimolting silkworms were induced by the treatments with both the imidazole compound "KK-42" hating anti-juvenile hormone activity and high temperature, and their growth, dietary efficiency, cocoon and cocoon filament qualities were compared with those of normal tetramolters as control. 1. The percentage of precocious trimolters was higher in the application of KK-42 than the treatment of high temperature. The effective concentration of KK-42 was 10$\mu\textrm{g}$/1arva. The high temperature treatment for 48 hour was more effective than 36 hour treatment, and silkworm larvae fed on mulberry leaves were more sensitive than artificial diet to induce trimolters. 2. The larval duration of the trimolters induced by KK-42 was 5.17 day shorter than that of normal tetramolters in mulberry leaves rearing, and the increasing pattern of body weight in the 4th inster larvae of trimotlers was similar to the 5th instar larvae of normal tetramolters. 3. The qualities such as cocoon weight, cocoon layer weight and cocoon layer ratio of precocious trimolter induced by KK-42 were much lower those of normal tetramolters: the cocoon weight and cocoon layer ratio were 0.78g, 14.2cg and 18.4% in mulberry leaves rearing, and 0.86 cg, 10.3cg and 12.3% in artificial diet rearing, respectively. 4. The size of cocoon and cocoon filament was smaller in the precocious trimolter, both KK-42 and high temperature, as compared with that of the normal tetramolters. 5. The efficiency of cocoon layer production of the precocious trimolters by the KK-42 was lower than that of the normal tetramolters: amount of the cocoon layer production per 1g of dry mulberry leaves ingested was 7.97cg in the precocious trimotors, while 9.20cg in the normal tetramolters.

• Journal of Sericultural and Entomological Science
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• v.36 no.2
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• pp.124-129
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• 1994

In order to investigate the possibility of fine-size cocoon production by the use of imidazole compound, Trifumin, the cocoon and cocoon filament qualities, dietary efficiency and fibroin component were examined. cocoon size, cocoon weight and cocoon shell weight of trimolter were smaller than those of tetramolter. Cocoon shell weight of trimolter was 58% and 26% of that of tetramolter in the 3rd instar treated larvae and in the 4th instar treated larvae, respectively. Amount of cocoon shell produced per 1g dry matter ingested was 94% and 85% of that of tetramolter in the 3rd instar treated larvae and in the 4th instar larvae, respectively. The effects of Trifumin on the reeling tests were different according to the stage of the treatment. When Trifumin was treated at the 3rd instar larvae, reelability of cocoon filament, amount of cocoon filament, size of cocoon filament, reelability percentage and raw silk percentage of cocoon were 100%, 60%, 60%, 97% and 90%, respectively. When Trifumin was treated at the 4th imstar larvae, most of reelability tests were inferior to those of the 3rd instar treated larvae, but reelavility percentage was increased 13%. The Trifumin treatment did not affect the electrophoretic patterns of cocoon fibroin.