Scientists sequenced the complete genome of a fungus called Stemphylium sp. (strain Aa22) that lives inside wormwood plants without harming them. This fungus produces natural compounds called alkyl-resorcinols that can repel aphids and kill plant-damaging nematodes, making them potentially useful as organic pesticides. The researchers found the genetic instructions for making these compounds and determined that growing the fungus in liquid culture produces more of the useful compounds than growing it on rice, offering a promising path toward developing these natural biopesticides on a larger scale.