Farmers have new intelligence in the war on bugs, thanks to Oregon State University researchers who have discovered that insect resistance to pesticides is apparently time-sensitive. A poison’s effect varies widely depending on the time of day it’s applied; spraying at dusk can be up to three times more lethal than spraying at noon, for example. Farmers who learn their pests’ biorhythms can save money on pesticides, reduce contamination of the crop and groundwater, and slow the evolution of toxin-tolerant insects. The breakthrough is also important for chronopharmacology — the study of how humans respond differently to medical treatment and drugs depending on the time of day. But “every discovery brings deeper questions,” says Jadwiga Giebultowicz, one of the researchers on the four-person team, which has another year before its grant from the USDA runs out. They also plan to apply for an extension to further study pests’ biological clocks and eventually, Giebultowicz hopes, tweak the right genes to make the little buggers drop their guard.