Insecticides From Wild Tomato: Trichome Counts and Contents

Wild species of plants contain numerous non-nutritive, bioactive compounds known as “phytochemicals”. Many of these compounds cause the leaf to be less suitable for insect growth and may influence leaf palatability. A significant positive correlation was found between the intensity of wild tomato leaf trichomes (leaf hairs) and mortality of many vegetable insects. Type-IV and type-VI glandular trichomes on the leaves of three accessions of Lycopersicon hirsutum f. typicum; six accessions of Lycopersicon hirsutum f. glabratum; two accessions of Lycopersicon pennellii; and one accession of Lycopersicon pimpinellifolium were counted monthly (January to December, 2001). Crude extracts prepared from the leaves of each species were also prepared in n-hexane and chloroform, separated, purified, and quantified using GC/MSD for biochemical composition. Monthly variations in concentration of methyl ketones, sesquiterpene hydrocarbons, and sugar esters (glycolipids) were determined. Considerable variations in biochemical constituents among accessions were detected