IPM Technologies principal Dr Paul Horne favours an integrated approach combining pesticides, cultural controls and biological agents for controlling pests. He led a workshop for arable farmers in Ashburton. PHOTO: TIM CRONSHAW That’s a sure sign good wasps are working to remove unwanted insect pest populations in arable or other crops.
Other beneficial predators or parasitoids include ladybirds, but unlike wasp maggots they don’t, in gruesome fashion, eat their hosts inside out. Dissecting caterpillars is part of the job for the entomologist, who set up IPM Technologies in Melbourne to help farmers control pests with minimal use of pesticides. "I like pulling them apart ," Dr Horne said at an Ashburton workshop hosted by the Foundation for Arable Research (Far).
"Every farmer I’ve met if I show them a caterpillar they squash it." He said it was part of the approach to integrated pest management (IPM). "The reason it’s important is you can’t tell the level of parasitism in a caterpillar — you can’t tell if it is parasitised or not.
It’s a really important question because if it is parasitised you don’t need to do anything as it’s not going to turn into a moth. So the way to tell is to pull it apart. If it’s got a maggot inside of it then it’s parasitised.
" While growers could not stop this generation from eating a crop, they would know the next generation would not turn into a moth and lay 900 eggs, he said. Some wasp maggots busted out of a parasitise.
