Effect of saponins and apigenin mixtures on feeding behavior of the pea aphid, Acyrthosiphon pisum Harris

Abstract

Electrical penetration graphs (DC EPG) were used to monitor the feeding behavior of the pea aphid Acyrthosiphon pisum Harris (Hemiptera: Aphididae) exposed to mixtures of saponins: 3GlcA, 28AraRhaXyl medicagenic acid glycoside (MAG) and zanhic acid tridesmoside (ZAD) with flavonoid apigenin, on agarose-sucrose gels. In general, mixtures of saponins with apigenin incorporated into agarose-sucrose gels resulted in a reduction in both the number of aphid probes and delayed their duration. Aphid feeding on gels impregnated with mixtures of the tested chemicals also showed a reduction in salivation into the gels and elongation of passive ingestion from the gels (EPG patterns g-E1 and g-E2, respectively). There were significant differences among the feeding behaviors of the pea aphids on gels containing mixtures of either MAG or ZAD with apigenin. These differences were also depended on the concentration and proportions of these compounds.