Reactive oxygen species (ROS) are byproducts of fundamental metabolic processes in plants. Abiotic stress, such as drought, elevates production of ROS.

The emerald ash borer (Agrilus planipennis) is an invasive wood-boring beetle that has killed millions of ash trees since its accidental introduction to North America.  All North American ash species (Fraxinus spp.) that emerald ash borer has encountered so far are susceptible,