Nine eremophilane sesquiterpenes 1 – 9 , two flavonoids 11 and 12 , and two known pirrolizidine alkaloids 13 and 14 , were isolated from Senecio adenotrichius DC . Their structures were elucidated on the basis of spectroscopic data and by comparison with previously reported spectroscopic data of similar compounds. Compounds 5 , 7 , and 9 have not been previously reported as natural products. The antifeedant activity of these compounds was tested against Spodoptera litoralis and Myzus persicae . Eremophilanes 1 , 3 , and 8 were strong antifeedants to M . persicae , and 1 and 8 to Spodoptera littoralis . Their ixodicidal activity was tested against the tick Hyalomma lusitanicum , with eremophilanes 1 , 3 , and 8 , being strong ixodicidal agents.