Blackmargined Aphid (Monellia caryella(Fitch); Hemiptera: Aphididae) Honeydew Production in Pecan and Implications for Managing the Pecan Aphid Complex in Texas

Abstract

Abstract. The blackmargined aphid, Monellia caryella (Fitch), was studied on three cultivars, ‘Cheyenne’, ‘Kiowa’, and ‘Pawnee’, of pecan, Carya illinoinensis (Wangenh.) K. Koch, in the field. Abundance of aphids and natural enemies (lacewings, ladybird beetles, and spiders) was determined twice weekly by directly inspecting foliage on each pecan variety during the summers of 2005 and 2006. Water-sensitive cards were used to measure honeydew deposited. Aphid phenologies were similar among pecan cultivars; however, Cheyenne supported more aphids than did Kiowa or Pawnee. Honeydew production was directly correlated with aphid abundance. Abundance of natural enemies increased during initial stages of aphid outbreak on all pecan cultivars, and the asymptote reached on Cheyenne exceeded the action level of 25+ aphids per leaf. Cheyenne had a lower natural enemy-to-aphid ratio than did the other cultivars, indicating that the functional response of natural enemies to increased aphid abundance was exhausted soon...