Investigations of the resistance of cabbage cultivars and breeders lines to insect pests at Wellesbourne

Abstract

The resistance of a wide range of cabbage material to several important insect pests was assessed in field experiments in five seasons at Wellesbourne. None of the 70 cultivars and breeders lines tested were found to possess resistance to all pests. Both non-preference for egg-laying and resistance to maggot damage were identified with respect to cabbage root fly (Delia radicum) attack; three red cabbage cultivars and two USA lines were the least damaged by maggots. There were no significant differences between 11 cultivars and lines in the number of plants infested by cabbage stem weevil (Ceutorhynchus pallidactylus). None of the cabbages was resistant to flea beetle (Phyllotreta spp.) attack and severity of damage was highly correlated with glossiness of plant foliage. The apparent resistance of one green and two red cabbage cultivars to cabbage aphid (Brevicoryne brassicae) early in the season changed as the plants aged; however, two US lines were consistently less damaged by aphids. High levels of resistance to lepidopterous pests bred into certain USA lines were confirmed for small white butterfly (Pieris rapae), cabbage moth (Mamestra brassicae), diamond-back moth (Plutella xylostella) and garden pebble moth (Evergestis forficalis). Two of these lines also possessed resistance to cabbage root fly and cabbage aphid.