Improving the pheromone lure for diamondback moth

Pheromone traps have potential to assist with integrated pest management of diamondback moth (Plutella xylostella (Linnaeus)). Trapping experiments were set up in brassica crops in Canterbury and Auckland to test the potential for improving lures for pheromone traps. Catch was improved with higher purity of synthetic lures containing (Z)-11-hexadecenyl acetate and (Z)-11-hexadecenal and (Z)-11-hexadecen-l-ol (30:60: 10). The initial lures tested caught 7.5% of the number of moths caught in traps baited with virgin females. This increased to 20-47% using better lures. Coupled gas chromatography and electrophysiology confirmed the presence of three active peaks from the chemicals listed above, plus a fourth unidentified compound. Traps with improved lures were used in a pilot IPM programme in Pukekohe and will assist brassica growers to minimse insecticide usage.