Flight activity and cereal host relationships ofRhopalosiphumspp. (Homoptera: Aphididae) in Canterbury

Abstract

Abstract Flight activity of Rhopalosiphum spp. was recorded in a suction trap between 1981 and 1987. Field studies on cereals in Canterbury during the period 1984–1987 showed that Rhopalosiphum padi L., the most frequent species, was usually present at low densities and only occasionally reached maxima greater than 10 aphids per tiller on wheat (Triticum aestivum L.) or barley (Hordeum vulgare L.). Greater numbers of R. padi were found on rye (Secale cereale L.) than on wheat, barley, oats (Avena sativa L.), or ryegrass cv Tama (Lolium perenne × multiflorum). Rhopalosiphum maidis (Fitch) was frequent on barley in 1985 and 1986 but was rare in other years. Rhopalosiphum insertum (Walker) and R. rufiabdominalis (Sasaki) were recorded on cereals in autumn 1987. Comparison of suction trap catches and numbers of winged aphids landing on cereals showed that R. padi concentrated on barley crops to a lesser extent than did R. maidis or Metopolophium dirhodum (Walker).