Insecticidal and nematicidal essential oils from Argentinean Eupatorium and Baccharis spp.

The defensive properties against insects and plant–parasites nematodes (antifeedant action against the aphids Myzus persicae and Ropalosiphum padi and the nematicidal effects on the root-knot nematode Meloidogyne javanica ) of essential oils from Argentinean semi-arid plants have been studied in relation with their chemical composition. The major components of Baccharis salicifolia essential oils obtained from samples collected from two locations (A and B) in San Luis (Argentina) were ( Z )-β-ocimene, germacrene D, muuroladiene and β-cubebene, with the addition of α-thujene and α-phellandrene, in location A and isoledene in location B. The essential oils of the Eupatorium species ( Eupatorium buniifolium , Eupatorium inulaefolium , Eupatorium arnotii , and Eupatorium viscidum ) have been previously described. M. persicae was strongly affected by these oils except for E. buniifolium and E. arnotii . Additionally, the essential oil from B. salicifolia (location A) had post-ingestive toxicity to Spodoptera littoralis larvae without antifeedant effects. Among these oils, E. viscidum showed a strong nematicidal effect.