Exploration And Utilization Of 12a-hydroxyroteone From Tephrosia Purpurea

Tephrosia purpurea is a subtropical and tropical plant species, its extracts with excellent insecticidal activities against various species of insect pests. This plant species is an important resource for exploration and utilization of botanical insecticides.In order to determine 12a-hydroxyrotenone content in T. purpurea barks, 12a-hydroxyrotenone content in the barks of sixteen cultivars was determined, content fluctuation of 12a-hydroxyrotenone in this plant barks in different growth periods was tested, and effect of three kinds of chemical fertilizer on 12a-hydroxyrotenone content in this plant barks was also studied.12a-hydroxyrotenone content in the barks of sixteen cultivars ranged from 0.22% to 5.95%, the content of 12a-hydroxyrotenone in the barks of cultivars Gangxi 2 was remarkably higher than that of the other cultivars. When the seeds of T. purpurea were sowed in January, in November, the content of 12a-hydroxyrotenone in barks of this plant reached to the maximum value. When CaHPO4, Carbamide and K2SO4 were used as fertilizer at the dosage of 20Kg/667m~2,5Kg/667m~2, and 5Kg/667m~2, the corresponding production of 12a-droxyrotenone in the barks of cultivar Gangxi 2 was 75.33 Kg,66.34Kg and 64.26Kg, and the production of 12a-hydroxyrotenone increased remarkably due to the usage of CaHPO4. Cultivars Gangxi 2 is an excellent plant resource for exploring of botanical insecticides, the best harvest period of this barks is in November, and CaHPO4 is helpful to increase production of 12a-hydroxyrotenone.The control effect of 9% 12a-hydroxy-rotenone Emulsion in water (EW) against three pests of rice (larva of Cnaphalocrocis medinalis Guenee, Sogatella furcifera and Nilaparvata lugens) was studied through field experiment. The results showed that 9% 12a-hydroxy-rotenone EW had a great control effect against these three pests showed above. At the concentration of 80-100 mL/mu, to control larva of Cnaphalocrocis medinalis Guenee, 9% 12a-hydroxy-rotenone EW not only had high control efficiency, but also had fast and long control effect. At the concentration of 100-120 mL/mu,9% 12a-hydroxy-rotenone EW had high and fast control effect against Sogatella furcifera and Nilaparvata lugens in the field. Therefore,9% 12a-hydroxy-rotenone EW is recommended to control the pests of rice.