유약(幼若)홀몬에 관한 연구(硏究) -유사(類似) 합성유약(合成幼若)홀몬 ″R-20458″에 대한 증사효과(增絲效果)- = Effect of Juvenile Hormone Analogs on Silkworm, Bombyx mori L. -Effect of Juvenile Hormone Analog ″R-20458″ on Increase of Silk Productivity by Topical Application-

국문 초록 (Abstract)

곤충홀몬에 대한 연구가 시작된 이래 그 작용 계작 및 화학적 구조가 밝혀지면서 합성유약홀몬의 개발과 빈용화가 활발히 진행되었다. 그 결과 살충제로써 실용가치가 인증되는 한편 누에에 있어서는 유충기간의 연장으로 증사효과가 기대되고 있다. 현재 미국의 Zoecon사와 Stauffer사에서는 누에의 증사제로써 "Manta"와 "R-20458"을 개발하였고 "Manta"는 일본에서 이미 시판하고 있다. 본 실험에서는 "Manta"를 보조대조로 "R-20458"에 대한 증사제로써의 실용성을 비교 실험한바 그 결과를 요약하면 다음과 같다. 1. "Manta"와 "R-20458"을 5령향식 후 51시간째에 경피처리하면 대조 무처리에 비해 처리구 공히 5령 경과일수가 12시간~1일이 길어졌다. 2. 화용비율에 있어서는 무처리대조와 두 공실약제간에 유의차가 없어 약해가 인정되지 않았고 두 약제간에도 차가 없었다. 3. 수견량에 있어서는 무처리대조구의 20.4kg에 비해 약제처리구는 전견중의 증가로 인하여 "Manta" 2.5ppm구는 22.2kg로 지수로 9%가 증수되었으나 "R-20458"의 경우는 5ppm구가 21.4kg로 지수로 5%, 2.5ppm구가 20.7kg, 1ppm구는 20.6kg으로 지수로 각각 1%가 증수되었다. 4. 견층비율에 있어서는 "Manta" 2.5ppm구가 25.6%로 무처리대조 24.1%에 비해 지수로 6%가 높았고 "R-20458"은 2.5ppm구가 25.0%로 지수로 4%, 1.25ppm구 및 5ppm구는 각각 24.9% 및 24.7%로 지수로 3% 및 2%가 높았다. 따라서 대1만두견사량에 있어서는 "Manta" 2.5ppm구가 15%나 증수되어 가장 높았고 "R-20458"은 5ppm구가 8%, 2.5ppm구는 5% 및 1.25ppm구는 4%가 증수되었다.

다국어 초록 (Multilingual Abstract)

Research on the hormones of insect has followed by the special opportunities and problems arising from pollution. Since then, the main frame of it has been energetically exploited by ligation, decapitation and so on. In the meanwhile, knowledge of the biochemistry of hormone action as well as other aspects of biochemistry in insects has been gradually disclosed. Since 1966, practical use of active analogs of the hormones has been also worked out as an insecticide and brought the features of it to the light. On the other hand, it is expected to afford the increase of silk productivity resulted from control of the fifth larval period by delaying normal development. With these regards, some of analogs have been tried to apply practically to the silkworm. One of them is "Manta" produced by Zoecon Chemical Company and it is presently used for the increase of silk productivity in Japan. Another one is "R-20458", not registered one, issued by Stuffer Chemical Company. It is still pending for the silkworm growth regulator. For the possibility of practical use, two chemicals are tested on the increase of silk productivity by topical application and the obtained results are summarized as follows. 1. It is evident that the fifth larval period was extended by topical application of the tested chemicals "Manta" and "R-20458" at the fifth instar after 51 hours of the last ecdysis, ranging from 12 hours to one day, as compared to the control. 2. In survival rates, there is no significance at 5% level between control and treatments. It proved that there was no toxity to silkworm by topical appication. 3. There is an increase of cocoon yield in both chemical treatments. It was resulted from increase of weight of single cocoon. "Manta" 2.5ppm produced 22.2kg of cocoon. It is equal to 9% increase in index, as compared to that of control. In case of R-20458, the increasing rates were varied at the different concentration; 21.4kg of cocoon production with 5% increase at 5ppm, 20.9kg of it with 2% increase at 2.5ppm and 20.6kg of it with 1% increase at 1.25ppm in index, respectively, as compared with that of control. 4. Percentage of cocoon shell was increased by topical application. In case of "Manta" 2.5ppm, it is 25.6% which is equal to 6% increase in index, as compared with that of control. For "R-20458", the increasing rates of percentage of cocoon shell were varied with the different level of chemical concentration. They are 25.0% of 4% increase at 2.5ppm, 24.9% of 3% increase at 1.25ppm and 24.7% of 3% increase at 5ppm. 15% increase was attained at "Manta" 2.5ppm in the weight of cocoon layer based on cocoon yield and percentage of cocoon shell in index, as compared with that of control. The rates for "R-20458" are 5% increase at 2.5ppm and 4% increase at 1.25ppm in index.