Researchers tested seventeen types of fungi found in Greek olive groves to see if they could kill olive fruit flies, which damage about 30% of olive crops. They applied the fungi to fly pupae in soil and without soil, then tracked how many flies died and how much fungal growth appeared. Several fungi types, especially Aspergillus flavus and A. keveii, were very effective at killing the flies and could potentially replace harmful chemical pesticides used in olive farming.