© 2021 Entomological Society of Turkey. All rights reserved.The planthopper, Orosanga japonica (Melichar, 1898) (Hemiptera: Ricaniidae), is an important agricultural pest of grapevine, kiwifruit and tea in Asia and in some countries of Eastern Europe. The efficacy of the crude extracts of Cuscuta campestris Yunck. (Solanales: Convolvulaceae) and Lupinus albus L. (Fabales: Fabaceae) plants was evaluated under laboratory conditions for control of O. japonica nymphs and adults collected in 2019 from Rize (Turkey). Their toxic efficacies were investigated by two different methods. Fixed-dose death rates were used for LT50calculation and dosage test results were used for LC50 calculation. Also, the phenolic constituents of active plant extracts were examined using HPLC-DAD. Generally, the LT50values obtained using ethyl acetate extracts were lower than those with methanol extracts. LT50values of adults were found lower than in nymphs. The test plants crude extracts had high activity at and below 2 g/L (LC90) for two different plants. HPLC-DAD results showed that the high concentration of kaempferol and quercetin for each extract. Extracts of both plants gave promising results for use in O. japonica control, but more detailed studies on the active constituents of these candidate plants need to be undertaken.