A new biotype of cabbage aphid (Brevicoryne brassicae(L.)) on Aphid Resistant rape (Brassica napusL.)

Abstract

The reaction of young plants of five varieties of Brassica napus L. to Brevicoryne brassicae (L.) from two sources was investigated in a glasshouse. Source I was a normal crop of Aphid Resistant rape carrying a small aphid population; source II was a severely-attacked crop of Aphid Resistant rape. Aphids from both sources caused severe leaf curling in Broad Leaf Essex rape, and those from source II caused medium to severe leaf curling in the varieties Aphid Resistant and Rangi rape, and Calder and Sensation swede. Some plants of an open-pollinated progeny of a naturalised rape plant were resistant to leaf curling caused by aphids from source II. The aphids from the two sources have been designated biotype NZ-1 and biotype NZ-2; the latter is the first biotype of B. brassicae to attack Aphid Resistant rape severely.