Responses of Tetranychus urticae (Koch, 1836) and Neoseiulus californicus (McGregor, 1954) to the application of salicylic acid on bean cultivars.

Abstract

This study evaluated the influence of exogenous application of salicylic acid in common bean (Phaseolus vulgaris L.) in Fepagro26 and Garapiá cultivars on the biology and chemotaxis response of T. urticae and, N. californicus. The experiments were carried out in an acclimatized room at 25±ºC, UR 70 ± 10% and photophase for 16 hours. To verify the doses of AS in contrast to oviposition of T. urticae, three females of the mite were placed per plant/cage after 48 hours of application of the treatments: leaf with water, leaf with water + 1% alcohol, leaf with water + 5% alcohol, 0.5mM, 1mM and 2.5mM salicylic acid. Oviposition was monitored daily for 96 hours and the results were submitted to factorial ANOVA. Both cultivars showed interaction between AS doses and number of T. urticae eggs. The regression analysis between AS doses and number of eggs showed a correlation only for Garapiá (R2 = 99.54). The attractiveness of T.urticae was verified in a dual-choice olfactometer (Y), where the phytophage was attracted by the combination of the cultivar Garapiá and application of a 0.5 mM dose of AS (p < 0.01). For N. californicus, the attractiveness was also verified in a dual-choice olfactometer (Y), where only volatiles from cv. Fepagro26 plus the presence of T. urticae (48h after infestation) triggered responsive chemotaxis behavior. These results suggest that AS can be a promising tool in the integrated pest management of this phytophagous, but in the studied cultivars it influenced the chemotaxis orientation of the predator.