Endolichenic fungi represent an important ecological group of microorganisms that form associations with photobionts in the lichen thallus. These endofungi that live in and coevolve with lichens are known for synthesizing secondary metabolites with novel structures and diverse chemical skeletons making them an unexplored microbial community of great interest. As part of our search for new phytoprotectans, in this work we studied the endolichenic fungus Xylaria sp. isolated from the lichen Hypogymnia tubulosa, which grow as epiphyte on the bark of the endemic tree Pinus canariensis. From the extract of liquid fermentation, we isolated two new piliformic derivatives, (+)-9-hydroxypiliformic acid (1) and (+)-8-hydroxypiliformic acid (2), along four known compounds, (+)-piliformic acid (3), hexylaconitic acid A anhydride (4) and two hydroxyphenylacetic derivatives (5-6). Their structures were elucidated based on NMR and HRESIMS data. The extract and compounds were tested for their antifeedant (Myzus persicae, Rhopalosiphum padi and Spodoptera littoralis), antifungal (Alternaria alternata, Botrytis cinerea and Fusarium oxysporum), nematicidal (Meloidogyne javanica) and phytotoxic effects on mono and dicotyledonous plant models (Lolium perenne and Lactuca sativa). Among these compounds 4, 5 and 6 were effective antifeedants against M. persicae and 4 was also active against R. padi. Moreover, compound 3 and 4 showed antifungal activity against B. cinerea and 4 was the only nematicidal. Phytotoxic test showed that the extract has strong effect against L. sativa and L. perenne growth. The phytotoxic compounds were 3, 4 and 5. (+)-Piliformic acid (3) and hexylaconitic A anhydride (4) displayed root growth stimulation on low doses and inhibitory effect at higher doses of dicotyledonous specie L. sativa.