NSW Department of Primary Industries principal research scientist, Hanwen Wu, said research has identified eucalyptus essential oils which have the potential to address agrochemical resistance in these pests. 

“The allelopathic effect of eucalyptus trees, where chemicals they release suppress plant growth in the understorey, is commonly seen in the landscape and we applied a scientific approach to investigate that observation,” Dr Wu said.

“Laboratory tests showed that some eucalyptus oils, from a selection of 40 species, were able to completely suppress fungal growth of three major diseases, wheat yellow leaf spot and crown rot and canola sclerotina stem rot,” he said.