Sunday, July 3, 2022

Moth can detox insecticides

Genetic research has revealed why the diamondback moth, also known as the cabbage moth, is one of the world’s worst agricultural pests.

The moth, which is a major pest in New Zealand, costs about $5 billion in global crop losses and control measures a year. It is highly fecund and capable of travelling long distances.

An international consortium, which included two Australian scientists, has cracked the moth's genetic blueprint showing how the caterpillars quickly develop resistance to insecticides.

Professor Geoff Gurr, from Charles Sturt University, said the moth's evolutionary trick lay in its ability to detoxify the defence compounds produced by plants in the cabbage family, the same compounds that make mustard pungent and cabbage smelly.

"Remarkably, it appears that the very genetic adaptations that allow the diamondback moth to cope with these natural compounds also allow it to detoxify the insecticides used against it," Gurr said.

Scientists believe cracking the moth's genetic code will allow new insecticide resistance monitoring techniques and pest management strategies to be developed.

The genetic research took 40 scientists several years to complete and identified 18,000 separate genes.

Two parasitoid wasps have been introduced to NZ and have become established as active biological control agents.

The moth breeds all year in NZ and feeds on brassica forage and vegetable crops. It has developed spray resistance here and advice is to use different chemistry each time. and FWplus

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