Abstract Continuing our search for natural product based compounds for the control of Brontispa longissima larvae, eight spin-labeled camptothecin derivatives 7a–h and the intermediate 2 were first tested for their insecticidal activities against fifth-instar larvae of Brontispa longissima. Among all the tested compounds, especially compounds 7a and 2 showed promising insecticidal activities with the corrected mortality rates of 69.55% and ...