• Journal of Sericultural and Entomological Science
• /
• v.39 no.2
• /
• pp.140-145
• /
• 1997

Silkworm fed on mulgerry leaves with 1000 times diluted Insegar(main component : Fenoxycarb, ethyl-2-(4-phenoxyphenoxy)ethylcarbmate) and its effects was investigated on increase of the 5th larval silkgland weight and silk quality. The oral application of fenoxycarb showed increase of the silkgland weight. The whole period of the silkgland weight falls on the 2nd instar treatment by 13%, the 3rd day of the 4th instar by 111%(3100 mg) and the whole period of the 5th instar treatment rather decreased it by 66%(497 mg), as compared to 1470mg of the control. Female and male both increased 15%(1779mg) and 12%(1554mg) of the silkgland weight with the 2nd instar treatment, as compared to 1548mg and 1391mg in control, respectively. 118%(3368mg) and 104%(2832mg) of increase in the silkgland weight were also showed with the 3rd day of the 4th instar treatment but 70%(463mg) and 61%(539mg) of decrease were shown with the 5th instar treatment. The maximum weight of the middle silkgland weight increased by 6%(1248mg) and 127%(2673mg) with the 2nd instar and with the 3rd day of the 4th instar, respectively but 67%(393mg) of decrease took place, as compared to 1175mg of the control. The maximum increase of the posterior silkgland weight with whole peried of the 2nd instar treatment increased 12%(419mg) and 75%(656mg) and 64%(135mg) of decrease was shown, as compared to 374mg of the control. The oral application of Insegar at the 2nd instar increased 26 m of cocoon length, 4.0 cg of the cocoon filament weight and 0.21d of the silk denier, as compared to 1147 m of the cocoon length, 38 cg of the cocoon filament, 2.99d of the silk denier, weight of cocoon filament and silk denier, respectively but denier variance narrowed to 0.33d, as compared to that of the control.

• Journal of Sericultural and Entomological Science
• /
• v.42 no.1
• /
• pp.24-27
• /
• 2000

A new silkworm variety 'Yangwonjam'for both of spring and autumn rearing season is F$_1$hybrid between Jam 143, a Japanese race bred from H5R1/P8503 and Jam 144, a Chinese race from M8312/8190. This is the first both parent sex-limited larval marking variety in Korea, and which contributes to eggs production of F$_1$hybrid silkworm with saving labor. Jam 143, Japanese parent of the 'Yangwonjam'showed high GCA in pupation percentage and Jam 144, Chinese parent showed high GCA in pupation percentage and single cocoon weight. In the local adaptability test performed at 8 local areas in spring of 1998, Yangwonjam records 1% higher in pupation percentage and 5%, 4% lower in single cocoon weight, cocoon yield from 10,000 3rd molted larvae respectively than the check variety Kumokjam. Also in the resistance test against unfavorable rearing condition performed in spring of 1997, Yangwonjam records 9%, 14% lower in single cocoon weight, cocoon shell weight respectively than the check variety, but showed 1% higher in pupation percentage than check variety.

• Journal of Sericultural and Entomological Science
• /
• v.32 no.1
• /
• pp.31-37
• /
• 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
• /
• v.36 no.2
• /
• pp.124-129
• /
• 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.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.10 no.2
• /
• pp.107-117
• /
• 2005

Oral supplementation of minerals mixture of potassium bromide and nickel sulphate on $CSR_2,\;CSR_4\;and\;CSR_2{\times}CSR_4$ crossbreed races with different concentrations (70, 110 and $160\;{\mu}g/ml$) were fed to the fifth instar larvae. Two of the four normal feeds per day was substituted with treated leaves fed to silkworm at fifth instar larvae. The controls were fed with the leaves sprayed with distilled water and normal leaves. The $CSR_4$ race treated larvae showed a significant increase in silkgland weight, cocooning percentage, female cocoon weight, male cocoon weight, male cocoon shell weight, male cocoon shell ratio, filament length, filament weight, denier, fecundity, number of eggs per ovariole and length of the ovariole when compared with those of the corresponding parameters of the carrier control, whereas in $CSR_2\;and\;CSR_2{\times}CSR_4$ crossbreed races showed a significant increase in larva1 weight and other parameters similar to that of $CSR_4$ race. The results suggested that the silkgland showed good response to minerals mixture of potassium bromide and nickel sulphate only in $CSR_4$ race when compared with those of other two races of the silkworm, B. mori.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.7 no.2
• /
• pp.117-125
• /
• 2003

To know the impact of female pupal weight corresponding to the male cocoon shell weight upon fecundity, hatchability and percentage of non-viable eggs, the experimental multivoltine breeds namely BL67 and 96A were categorised into low, medium and high batches according to the weight of female pupae and male cocoon shells and moths emerged from low, medium and high female pupae were allowed to mate withmoths emerged from low, medium and high male cocoon shells. Both the experimental breeds of BL67 and 96A revealed a fairl trend in fecundity for high batch ＞ medium batch ＞ low batch. When data were statistically analysed, a significant (p ＜ 0.05) and a highly significant (p ＜ 0.01) increase in fecundity was observed in the medium and high batches of BL67 during November - December, 2002 whereas highly significant (p ＜ 0.01) increase was observed in the high batches of 96A during November - December, 2002. Data revealed a highly significant (p ＜ 0.01) increase in fecundity in medium and high batches of both the breeds during January - February, 2003. More interestingly, a significant (p ＜ 0.05) reduction was noted in percentage of non-viable eggs in high batches of 96A during January - February, 2003. But no significant variation in hatchability was noticed due to the effect of differential female pupal weight and male cocoon shell weight.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.7 no.2
• /
• pp.191-195
• /
• 2003

The impact of antibiotic (Norfloxacin) administration ,at different concentration (50 ppm and 100 ppm) on commercial characters of bivoltine $({CSR_2}{\times}{CR_4})$ and the cross breed race $({BL_67}{\times}{CSR_101})$ was studied. The result indicated that antibiotic administration with different concentrations significantly improved the rearing and cocoon parameters like larval duration, larval weight, growth index, single cocoon weight, single shell weight and shell ratio. The post cocoon parameters like average filament length, non-breakable filament length, raw silk percentage, raw silk recovery percentage, denier, reelability and neatness were recorded significantly higher in antibiotic treated batches. The better performances of these parameters were recorded with the increase of antibiotic concentration.

• Journal of Sericultural and Entomological Science
• /
• v.36 no.1
• /
• pp.26-29
• /
• 1994

The topical application of methoprene a kind of juvenile hormone(JH) on 4th instar larvae at 48th hour after ecdysis-3 , followed by insulin on 5th instar larvae and silkgland weights, cocoon weight and cocoon shell weight, and fecundity ; and significantly decreases percent of cocooning and moth emergence. After treatment with methoprene followed by insulin, cocoon weight increase by 17~20% and cocoon shell weights by 18~32% respectively.

• Journal of Sericultural and Entomological Science
• /
• v.10
• /
• pp.67-72
• /
• 1969

In order to analyse the correlation between the parents and their hybrids in the silkworm, which were reared in spring, the author has surveyed the various quantitative characters which are significant in genetics, and the hybrid vigor rate. The duration of larvae life is shorter in F1 Value an in the mid parents value, cocoon size biffer, pupa rate, cocoon crop from ten thousand silkworms just molted in the fourth instar, total cocoon weight and cocoon layer weight increases in comparison with the mid parents value. Although cocoon layer ratio only shows increasing by 0.3％ or so, it is too little to admit the effect. F1 value is nearly equal to parent value and there is no correlation between F1 hybrids value and their mid parents value.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.4 no.2
• /
• pp.109-115
• /
• 2002

With the objective of selecting suitable breeding resource material, 10 polyvoltine and 10 bivoltine breeds were drawn from the germplasm collection of Central Sericultural Research and Training Institute, Mysore, and evaluated for 3 seasons comprising one year (6 trials). Data were collected on seven traits of economic importance such as fecundity, pupation rate, cocoon yield, cocoon weight, cocoon shell weight, cocoon shell ratio and filament length, and statistically analysed with two-way classification, Joint scoring method and evaluation index. Significant seasonal variations (P < 0.01) were observed in both polyvoltine and bivoltine breeds. Polyvoltines BL27, BL36 and BL54 and bivoltines CSR2, CSR4 and Daizo scored highest ranking values in all the three methods. Hybridization was initiated based on larval markings and cocoon shapes. Seasonal variations were discussed.