Effects of Various Synthetic Sucrose Esters on Weed Seed Germination and Crop Growth:  Structure−Activity and Dose−Response Relationships

Abstract

Twelve synthetic sucrose ester (SE) products with C7−C10 chain lengths and various degrees of esterification (DE) were tested for their influence on seed germination of prosomillet and velvetleaf and on growth of broccoli and bell pepper plants. At 100 ppm most SE caused virtually total inhibition of germination; at lower concentrations dose−response and structure−activity relationships were apparent. Sucrose esters with seven and eight carbon acyl groups were most effective, and activities 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 lowest DE (higher in monoacyl esters) was also less active. The biologically most active SE product was characterized by mass spectrometric techniques. 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. Structure−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 treated with the 12 SE samples, was not affected by concentrations far above those used for effective insecticidal action. Since the SE products are nontoxic to humans and higher animals, fully biodegradable, and not harmful to the crops tested, they appear to be good candidate insecticides. Potentials for suppression of weed seed germination need field evaluation. Keywords: Sucrose esters; dose−response; structure−activity; seed germination; crop growth; broccoli; bell pepper; Panicum milliaceum; Abutilon theophrasti

Mortality of Bemisia tabaci biotype B (sternorrhyncha: aleyrodidae) adults by aliphatic and aromatic synthetic sucrose esters

“…Although these products were appropriate for controlling the adult silverleaf whiteflies, the growers should also consider some other factors prior to the utilization. The effect of sucroesters on plant development, on the seed germination (Peterson et al 1997), and on the natural enemies should also be investigated. …”

“…An anionic surfactant, sodium dodecylsulfate (SDS) was also applied for the comparisons. Whiteflies bioassays were carried out with the adult insects collected from the cabbage plants using the yellow sticky strips with 4 x 4 cm of exposed surface (Chortyk et al, 1997). Nine strips (replicates) were used per treatment onto which ca.…”

“…Sucrose esters have been claimed as an alternative strategy to control the aphids and softbodied insects. The insecticidal activity of some natural and synthetic sucroesters has been reported (Liu et al, 1996;Chortyk et al, 1997). The natural sucroesters were obtained from several species of Nicotiana and Petunia.…”

“…The natural sucroesters were obtained from several species of Nicotiana and Petunia. These sucroesters were mainly formed by different carboxylic acids whose chains varied from C 2 to C 12 (Chortyk et al, 1996;Chortyk et al, 1997). It seems that sucroesters have a physical action on insects.…”

The Biology of Canadian Weeds: 155.Panicum miliaceumL.

“…Some cucumber accessions have shown allelopathy to proso millet in the field [see section 13(c)]. Peterson et al (1997) tested 12 different synthetic sucrose esters for their ability to inhibit the germination of seeds of Panicum miliaceum and velvetleaf. Tests in Petri dishes revealed that ten of the synthetic sucrose esters could cause more than 90% inhibition of germination in P. miliaceum when applied at a concentration of 100 ppm and one of these esters could cause 80% inhibition at a concentration of 10 ppm.…”