Mortality of second-instar larvae of Tuta absoluta produced by the hexane extract of Lycopersicon hirsutum f. glabratum (PI 134417) leaves
1 The mortality resulting from exposure of second-instar larvae of Tuta absoluta to a hexane extract of Lycopersicon hirsutum f. glabratum (PI 134417) leaves was evaluated in the laboratory.
2 A crude hexane extract was fractionated on a silica gel column to produce 17 fractions. The toxicity of the fractions was evaluated on T. absoluta larvae at 2 and/or 6 mg/10 larvae/Petri dish along with a control.
3 Only two fractions, 4.50 and 10.18% of the total hexane extract, were found to result in very high mortality of second-instar T. absoluta.
4 All the 17 fractions were analysed by capillary gas chromatography/mass spectrometry (GC/MS). The two most toxic fractions were virtually identical and contained mainly undeca-2-one (2-UD) and trideca-2-one (2-TD).
5 A third major sub-fraction 13 (50.73% of the total hexane extract) was further fractionated on a silica gel column to obtain five additional sub-fractions. The toxicity of all the five sub-fractions was evaluated using second-instar T. absoluta at 2 mg/10 larvae/Petri dish and also analysed by GC/MS. The most toxic sub-fractions contained mostly 2-UD and 2-TD.
6 The results suggest that 2-UD and 2-TD could be related to resistance of L. hirsutum to T. absoluta.
Document Type: Research Article
Affiliations: 1: Departamento de Química, LPPN (Laboratório de Pesquisa de Produtos Naturais), Universidade Federal de Viçosa, Viçosa, Minas Gerais 36571-000, Brazil, 2: Departmento de Biologia Animal, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36571-000, Brazil and 3: Departamento de Química, Universidade Federal de Brasília, Brasília, DF, 70.910-970, Brazil
Publication date: 2001-11-01