Plants emit volatile chemicals, which may attract insect herbivores and associated predators or parasitoids. Insect feeding or mechanical injury may influence the release of these chemicals. Five types of plant wounding were imposed after the Zadoks 32 growth stage was reached and volatiles were collected from the main stem. The volatile collection sequence used was two consecutive ten-hour collections to obtain the samples in either daylight or darkness. The first sampling period was immediately after the injury, followed by sampling at 2 and 4 days. The volatiles collected were analyzed by coupled gas chromatography-mass spectrometry (GC-MS). Damage to wheat stems or leaves increased the production of the secondary metabolites, linalool (C₁₀H₁₈O) and linalool oxide (C₁₀H₁₈O₂). The amount released was greater during the day, and was also influenced by the type of the injury. In some cases, enhanced volatile chemical production continued for 4 days following the injury.