Effects of Aqueous Extracts of Endophyte-Infected Grass <i>Achnatherum inebrians</i> on Growth and Development of Pea Aphid <i>Acyrthosiphon pisum</i>

Abstract

The pea aphid Acyrthosiphon pisum has a worldwide distribution and causes serious losses for agricultural production. Drunken horse grass Achnatherum inebrians is a widely distributed perennial poisonous grass on the grasslands of Northern and Northwestern China. The present study focused on contact toxicity activity of aqueous extracts of endophyte-infected (E+) and endophyte-free (E−) A. inebrians in different growth periods of pea aphids, and the growth and development of two color morphs of F1 generation nymphs. Both of the color morphs had development durations in E+ treatments that tended to be longer at 1st, 2nd, 3rd, and 4th instars than E− and control (CK). The E+ treated aphids also showed decreased weights at maturity with over all lower mean relative growth rates (MRGR). Aphid survival of E+ treated aphids was lower than that of E− and CK at all growth periods. Seeding stage E+ extracts showed a greater propensity for negatively affecting aphids than did E+ extract at maturity and the yellowing stage. These results show that extracts from endophyte-containing plants may contain compounds that may be used to control insects.

Keywords

• <i>Achnatherum inebrians</i>
• <i>Acyrthosiphon pisum</i>
• growth and development
• aqueous extract