The green leaves of commercial N. tabacum types are generally covered with gummy exudates, which are produced by leaf trichomes, and are precursors of important tobacco and tobacco smoke flavor and aroma components. Cuticular extracts of green tobacco have been separated and quantitated by gas, thin-layer, and high pressure liquid chromatography. Major components in trichome exudates are duvane diterpenes (a- & beta-4,8,13-duvatriene-1,3-diols and a- & beta-4,8,13-duvatrien-1-ols), labdane diterpenes (Cis-abienol- and 13E -labda-13-ene-8alpha-15-diol) and/or sucrose esters (6-0-acetyl-2,3,4-tri-0-acyl - sucrose). Commercial U.S. flue-cured and Burley tobaccos produce duvanes and low levels of sucrose esters with butyric and methylbutyric acid moieties. In contrast, duvanes, labdanes, and sucrose esters with methylbutyric and methylvaleric acid moieties are important cuticular components of Oriental tobacco types. The levels of these componets are affected by genetics, stage of plant development, and environmental and agronomic conditions. As the leaf matures, trichome synthesis of diterpenes and sucrose esters stops and oxidative degradation of the initially formed diterpenes begins and continues through curing and aging. In contrast, the sucrose esters are retained essentially unchanged. During the smoking process the acid moieties of the sucrose esters are liberated. The beta- methylvaleric acid flavor trait of cigarette smoke of many Oriental tobacco types results from high levels of 3-methylvaleric acid moieties in the sucrose esters.