Jk. Peterson et al., EFFECTS OF VARIOUS SYNTHETIC SUCROSE ESTERS ON WEED SEED-GERMINATION AND CROP GROWTH - STRUCTURE-ACTIVITY AND DOSE-RESPONSE RELATIONSHIPS, Journal of agricultural and food chemistry, 45(12), 1997, pp. 4833-4837
Twelve synthetic sucrose ester (SE) products with C-7-C-10 chain lengt
hs and various degrees of esterification (DE) were tested for their in
fluence on seed germination of prosomillet and velvetleaf and on growt
h of broccoli and bell pepper plants. At 100 ppm most SE caused virtua
lly total inhibition of germination; at lower concentrations dose-resp
onse and structure-activity relationships were apparent. Sucrose ester
s with seven and eight carbon acyl groups were most effective, and act
ivities decreased for nonanoyl and decanoyl esters, respectively. With
respect to DE, products high in di-, tri-, and tetraacyl esters were
most active. Increased DE caused decreasing activities; however, the l
owest DE (higher in monoacyl esters) was also less active. The biologi
cally most active SE product was characterized by mass spectrometric t
echniques. The product consisted of 7.5% monoheptanoyl and 20.7% di-,
33.5% tri-, 23.6% tetra-, 7.7% penta-and 1.3% hexaheptanoyl esters. St
ructure-activity relationships with respect to published insecticidal
activities paralleled their germination inhibitory effects. Growth of
young broccoli and bell pepper plants, the leaves of which were treate
d with the 12 SE samples, was not affected by concentrations far above
those used for effective insecticidal action. Since the SE products a
re nontoxic to humans and higher animals, fully biodegradable, and not
harmful to the crops tested, they appear to be good candidate insecti
cides. Potentials for suppression of weed seed germination need field
evaluation.