Pesticides may influence levels of secondary metabolites like flavonoids, hydroxycinnamic acids, anthocyanins, tropane alkaloids, and volatile terpenoids by non-specific mechanisms or interfering the key biosynthesis steps. The quality of volatile oils can be altered by changing their chemical composition, especially the toxic or useful constituents. Moreover, pesticide residues can be solubilised in volatile oils. Also, pesticides are able to modulate plant metabolism affecting assimilation rate of micronutrients.
The complete assesment of plants exposed to pesticides requires knowledge of the biochemical and physiological responses of vegetal organisms to these substances in order to understand the magnitude of the agrochemicals action, but also for the rational engineering of plant secondary metabolites.