served, however, and we feel that the severed area contributes only a minor amount to the total volatiles. There seems no other practical way of obtaining the volatiles from the leaves without introducing other artifacts from the soil, environment, plastic containers, etc. The volatile compounds in macerated wheat leaves reported by Hamilton- Kemp and Andersen (1984) are quite different from those found in the present work. As discussed in previous work [e.g., Buttery and Ling (1984)], damage to the plant material (maceration would cause extreme damage) gives rise to considerable oxidative enzyme activity that breaks down the plant lipid and carotenoid components to a relatively large amount of volatile aliphatic aldehyde and alcohol compounds that are not present in the intact plant [cf. Schwimmer (1981)]. Such enzyme-produced volatiles can completely obscure the original volatiles that may be 100 times less in concentration. The enzyme action might also destroy (e.g., oxidise) some of the volatiles present in the intact plant. To fully understand the attraction of insect pests to their specific host plants, it would seem of primary importance to identify the compounds emitted by the intact plant.Volatiles emitted by damaged plants may also be important in the attraction of certain insect pests.