While working to stop bollworms destroying cotton crops, Dr Robert Mensah wondered whether other insects could provide a solution
While trying to come up with a pesticide solution to kill off bollworms, Dr Robert Mensah had his eureka moment.
It was the 90s, and in Australia bollworms were devastating cotton farms, with the larvae of these moths chomping up the crops faster than farmers could eradicate them. The farmers were trapped in an arms race with the bollworms, applying more and more pesticide to combat an increasingly resistant species of pest – killing many beneficial insects in the process.
Instead of carrying on down the death spiral, Mensah, an entomologist working at the Cotton Research Institute, began to wonder whether it might be possible to get another insect in to do the job. He experimented and eventually came up with a simple food spray, “a mixture of food ingredients, yeast and sugar-based, diluted in water and applied to crops. It emits an odour which is picked up by beneficial predatory insects and attracts them to the fields where they kill pests.”
He started testing it out in the fields and found that food sprays could entice useful predators such as ladybirds and lacewings. A refuge crop of evergreen alfalfa flowers could also support their populations year-round, so they wouldn’t leave at the end of the season and be poisoned by pesticides in the surrounding landscape. It was the beginning of an international grassroots campaign, in which Mensah has worked with various charities to teach people about this sustainable farming method.
