(Radio Iowa) – Researchers say information they’ve discovered might change how conservationists should deal with the invasive species known as garlic mustard. Garlic mustard blocks out light from other plants and ISU researcher Cathy McMullin says the data she is following shows it also releases chemicals that prevent the seeds of other plants from growing.  “Native plants and their associated — what we call mycorrhizal fungi — appear to be developing a resistance to garlic mustard allele chemicals. And this increases with the time of exposure to garlic mustard. So the resistance increases,” McMullin says. She says the older the population of garlic mustard is, the fewer toxic compounds it produces.

“This is likely due to the cost of producing these allele chemicals,” McMullin says. “They take a lot of carbon and a lot nutrients to produce them. And if the yields are diminishing than selection kind of suggest its not worth producing these anymore.” McMullin is an adjunct associate professor in the Department of Natural Resource Ecology and Management at Iowa State University. She says for those trying to keep new garlic mustard from taking root, spring is the right time to be pulling it out of the ground. For more mature garlic mustard, she recommended removing the seed head, preventing them from maturing and entering the seed bank.

McMullin made her remarks on Wednesday’s Talk of Iowa on Iowa Public Radio.