Salicylic acid as an inducer of arthropod-pest resistance in tomato

Resumo

The aim of this study was to evaluate the effect of exogenous application of salicylic acid as an inducer of resistance to two-spotted spider mite and tomato pinworm in tomato genotypes. For this, bioassays were carried out in commercial (‘Redenção’, ‘Giuliana’, and ‘Alambra’) and wild (Solanum habrochaites var. hirsutum accession ‘PI-127826’) genotypes. Walking of the two-spotted spider mite was determined on the leaflets, as well as the number of eggs and caterpillars and the percentage of leaf area consumed by the tomato pinworm by means of leaflet scanning. Furthermore, the damage caused to plants was evaluated using a rating scale for damages, types of lesions, and percentage of attacked leaflets. The salicylic acid application generated resistance in the commercial genotypes against both pests. However, a higher resistance was observed in the accession ‘PI-127826’ when compared to the other genotypes, even little responsive to the salicylic acid application. This indicates that their resistance is due to constitutive defense, whereas in commercial genotypes the defenses are dependent on salicylic acid-mediated induction responses, at least in part.