Dispersal of the Grain Aphid Macrosiphum miscanthi from Australia to New Zealand

Abstract

Trans-oceanic dispersal of alate aphids (Hornoptera: Aphididae) \\.as first noted by Elton (1925), who found live aphids on the snows of Spitzbergen and suggested they had come from Kola Peninsula. northern U.S.S.R., a distance of 1300 km. Insects have been trapped on ships at sea, and in one such study off the coast of Argentina, Holzapfel. Tsuda and Harrell (1970) t~apped 2 aphids 1100 km from land, and one at 1500 km. In the Australia-New Zealand region the presence of certain aphid species on Macquarie (Eastop, 1962) and Campbell Islands (Cottier, 196-1) suggests dispersal of alatae from Australia or New Zealand. The grain aphid Macros~pl~um miscantlzi Takahashi has been present in Australia for many years (Eastop, 1966). In New Zealand it had been found on native grasses (Cottier, 1953), but not on ccreals. preliminary account of the development on this aphid to pest proportions on cereals is given by Lowe, who, in 1966, recorded the aphid on cereals and grasses in the North Island and in the northern part of the South Island, and in 1967 in Canterbury (Lowe, 1969).