Role of plant age in the resistance of Lycopersicon hirsutum f. glabratum to the tomato leafminer Tuta absoluta (Lepidoptera: Gelechiidae)

The objective of this work was to study the role of plant age in the resistance of tomato, Lycopersicon hirsutum, to the tomato leafminer Tuta absoluta (Meyrick). Determination of the levels of tridecan-2-one and undecan-2-one in L hirsutum were made at three different ages (2-4 months after germination), as well as the leaf area, and the density and types of trichomes present on L. hirsutum and L. esculentum. This information gathered was correlated with the following biological characteristics of ir: absoluta: rates of oviposition and egg eclosion; length of egg, larval and pupal stages; mortality in the larval and pupal stages; pupal weight and proportion of females. I: absoluta showed higher oviposition and egg eclosion, as well as lower mortalities and shorter larval and pupal periods in L. esculentum than in L. hirsutum. The proportion of females obtained was also higher on L. esculentum. The rate of egg eclosion and proportion of females as well as the length of the larval stage and the mortality of larvae appeared to be affected by plant age. A higher proportion of females, mortality of larvae and length of the larval period were obtained with older plants of L. hirsutum, while the rate of egg eclosion, was higher for L. hirsutum plants that were 3 months old. For L. esculentum, plant ageing increased larval mortality. It seems that the glandular trichome density in L. hirsutum increased with plant age leading to an increase in the levels of tridecan-2-one, which slows larval development, (C) 2001 Elsevier Science B.V. All rights reserved.