A non-toxic treatment that confuses mice could help prevent a repeat of the 2021 mouse plague that caused $1 billion in damage, and may have applications for a variety of crops. Sydney University researcher say a diluted wheat germ oil sprayed on wheat seeds acts as an "odour camouflage" and stops mice from making a meal out of new crops. The researchers found that mice dug up to 74 per cent fewer wheat seeds when the seeds were sprayed with the oil a week before sewing. "Knowing that it does work is the key step," said conservation scientist Peter Banks who co-authored the research. At the height of the 2021 mouse plague when the rodents were running rampant in wheat paddocks across NSW, the team carried out a series of trials at a wheat farm at Pleasant Hills in the state's south. "Mice want to search for the easiest food options ... we kind of forced them to switch and look for something easier to find," said PhD student Finn Parker who led the research. "Creating this blanket smell of wheat on the surface of the soil, such that mice weren't able to use it as a reliable cue for where the seeds were," he said. Professor Banks got the idea for the wheat germ oil when he noticed just how precise mice are when digging up paddocks, in a picture showing the damage they caused. "I thought they're smelling the seed, they have to be," Prof Banks said. "When that smell is everywhere, they can't work out where that seed is," he told AAP. While the trials related to wheat, the scientists believe it could also be applied to other crops and might even help in the back yard. "People have got animals digging up seeds in their vege patch, if there is parsley seeds being dug up, parsley seed oil maybe might work?" said Prof Banks. The researchers say more work is needed to determine how much and how often the oil needs to be applied for it to be effective, which would then determine the cost. The research is published in Nature Sustainability.