CHARACTERIZATION OF INSECTICIDAL SUGAR ESTERS OF PETUNIA

The recent finding that leaf surface glycolipids of Petunia x hybrida Hort. plants possess insecticidal activity against sweetpotato whitefl ies prompted a search for the specific compounds responsible for this biological activity. Successive liquid chromatographic fractionations of an extract of cuticular chemicals of Petunia plants yielded distinc t fractions of two glucose esters and four sucrose esters. These diffe rent structural types of sugar esters were identified to be 2,3,4-tri- O-acyl-alpha- + beta-D-glucopyranose, 2,3,4,6-tetra-O-acyl-alpha- + be ta-D-glucopyranose, yl-alpha-D-glucopyranosyl-beta-D-fructofuranoside, ucopyranosyl-(6'-O-acetyl)-beta-D-fructofuranoside yl-alpha-D-glucopy ranosyl-beta-D-fructofuranoside, and copyranosyl-(6'-O-acetyl)-beta-D- fructofuranoside, where the major acyl constituents were 2-methylbutyr yl, hexanoyl, 4-methylvaleryl, and heptanoyl groups. Bioassays of the individual sugar esters against adult sweetpotato whiteflies revealed that the majority of the activity was produced by tri- and tetra- subs tituted sucrose esters, while highly substituted sucrose or glucose es ters were weakly toxic or completely inactive.