Australian aphid trials continue
The Western Australian Department of Agriculture and Food is to continue its trials of aphid management schemes to determine the threshold at which insecticide applications on canola crops are economically justified. Cabbage aphids ( Brevicoryne brassicae) will be introduced at different times during late winter and spring, but allowed to feed for limited periods of time. Last year, the trials assessed the impact of unlimited feeding by the pest on early flowering canola. Damage by cabbage aphids varies from year to year and some growers apply the only insecticide registered for use on canola, pirimicarb, as a preventative measure rather than in response to severe infestation. Although cheap and sometimes effective, the sustainability of using pirimicarb without monitoring aphid levels is questionable, says Department development officer Dusty Severtson.