Insecticidal effects of Ungernia severtzovii bulb extracts against the grain aphid Schizaphis graminum (Rondani)

Insecticidal effect of Ungernia severtzovii bulbs extract has been investigated against the grain aphid Schizaphis graminum. LC50 value of the ethanolic extract of U. severtzovii against the female aphids was 0.235% (2.35 g/l). There was 100% mortality of the subsequent nymphs of the treated females at 0.25–1.0%. The extract was equally active against the nymphs at the highest concentrations. Hexane and ethanolic extracts were the most active against the aphids of all the extracts. Fractionation of the hexane extract by TLC yielded three fractions. Fraction II was the most active (>90% mortality) against the aphids. Xanthoxylin was identified as the major constituent in fraction II of the hexane extract and may be responsible for the insecticidal effect of U. severtzovii.

► We investigate the active compounds from U. severtzovii bulbs. ► The U. severtzovii extract showed contact-intestinal activity against S. graminum. ► The active principle of the extract is acetophenone xanthoxylin. ► It is the first time that its isolation from U. severtzovii has been reported. ► We consider that xanthoxylin is potentially valuable agent for use as insecticide.