Kentucky State University
Phytochemicals for Pest Control
Institution
Kentucky State University
Faculty Advisor/ Mentor
George F. Antonious
Abstract
Several wild tomato accessions of Lycopersicon hirsutum that are not consumed by humans were planted under greenhouse conditions for mass production of leaves. The foliage of the wild tomato Lycopersicon hirsutum f. glabratum (Mull); L. hirsutum f. typicum ( Humb & Bonpl.); and L. pennellii Corr. (Solanaceae) is covered with glandular trichomes (plant hairs). Glandular trichomes on the leaves of Lycopersicon hirsutum f. typicum; Lycopersicon hirsutum f. glabratum; Lycopersicon pennellii; and Lycopersicon pimpinellifolium were counted monthly. Trichome contents were separated, purified, and quantified using a gas chromatograph equipped with mass selective detector (GC/MSD) for biochemical composition. Considerable variations in biochemical constituents among accessions were detected. Two sesquiterpene hydrocarbons, zingiberene and curcumene, were found in L. hirsutum f. typicum. An average three month old plant of L. hirsutum f. typicum (PI-127827) has 1.30 kg fresh leaves averaging about 28,130 cm2 exposed leaf surface area produced 17.2 g zingiberene and 1.8 g of curcumene. Four methyl ketones (2-tridecanone, 2-dodecanone, 2-undecanone, and 2-pentadecanone) were found in L. hirsutum f. glabratum. Two methyl ketones, 2-undecanone and 2- tridecanone, having insecticidal activity against many herbivorus insects predominated hair secretions in five of the L. hirsutum f. glabratum accessions tested. Concentrations of total methyl ketones ranged from 81.3 µg/g fresh leaflets on L. esculentum cv. Fabulous (a commercial tomato cultivar) to 5.5 mg/g fresh leaflets on L. hirsutum f. glabratum.
Phytochemicals for Pest Control
Several wild tomato accessions of Lycopersicon hirsutum that are not consumed by humans were planted under greenhouse conditions for mass production of leaves. The foliage of the wild tomato Lycopersicon hirsutum f. glabratum (Mull); L. hirsutum f. typicum ( Humb & Bonpl.); and L. pennellii Corr. (Solanaceae) is covered with glandular trichomes (plant hairs). Glandular trichomes on the leaves of Lycopersicon hirsutum f. typicum; Lycopersicon hirsutum f. glabratum; Lycopersicon pennellii; and Lycopersicon pimpinellifolium were counted monthly. Trichome contents were separated, purified, and quantified using a gas chromatograph equipped with mass selective detector (GC/MSD) for biochemical composition. Considerable variations in biochemical constituents among accessions were detected. Two sesquiterpene hydrocarbons, zingiberene and curcumene, were found in L. hirsutum f. typicum. An average three month old plant of L. hirsutum f. typicum (PI-127827) has 1.30 kg fresh leaves averaging about 28,130 cm2 exposed leaf surface area produced 17.2 g zingiberene and 1.8 g of curcumene. Four methyl ketones (2-tridecanone, 2-dodecanone, 2-undecanone, and 2-pentadecanone) were found in L. hirsutum f. glabratum. Two methyl ketones, 2-undecanone and 2- tridecanone, having insecticidal activity against many herbivorus insects predominated hair secretions in five of the L. hirsutum f. glabratum accessions tested. Concentrations of total methyl ketones ranged from 81.3 µg/g fresh leaflets on L. esculentum cv. Fabulous (a commercial tomato cultivar) to 5.5 mg/g fresh leaflets on L. hirsutum f. glabratum.