Intensity of Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) and Liriomyza spp. (Diptera: Agromyzidae) attacks on Lycopersicum esculentum Mill. Leaves

Abstract

The objective of this study was to determine the effect of height of leaves in the canopy of plants, leaf organic compounds, concentrations of leaf nitrogen and potassium, leaf trichomes and cristalliferous idioblasts densities on the attack intensity of three tomato (Lycopersicon esculentum Mill. cv. Santa Clara) crops by Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and Liriomyza spp. (Diptera: Agromyzidae), under field conditions. The experimental design was arranged in randomized blocks, with three replications, each being one tomato crop. Analysis of variance and the Tukey s multiple range test (5% significance) were used to test the effect of canopy height, trichome and cristalliferous idioblasts densities on the number of mines produced by T. absoluta and Liriomyza spp. and on the number of T. absoluta eggs. Pearson s correlation (5% significance) was used to evaluate the relationships between leaf organic compounds, leaf N and K concentrations, leaf trichome and cristalliferous idioblasts densities and the number of mines produced by T. absoluta and Liriomyza spp. and the number of T. absoluta eggs. Highest insect attack occurred in the final stage of the culture. A higher number of Liriomyza spp. mines/leaf was recorded in the lower (1.50) than in the upper (0.02) level of the tomato plants, the opposite was observed for the number of T. absoluta eggs/leaf (0.13 and 0.57, respectively). The number of T. absoluta mines/leaf concentrated more on the median (10.23) and apical regions (8.63) than on the basal (4.93). No significant effect of the trichomes and cristalliferous idioblasts densities of leaves was noted on T. absoluta and Liriomyza ssp. populations. Apparently, the terpenes affected oviposition of T. absoluta while leaf potassium affected Liriomyza spp. attack.