Effect of the essential oil from the latex of the fruit Mangifera indica L. on Tetranychus urticae Koch (Acari, Tetranychidae)

Abstract

Tetranychus urticae Koch is a cosmopolitan pest that causes damage to crops in protected farming activities in the semiarid region of the state of Pernambuco, Brazil. We investigated the lethal and sublethal effects of the essential oil from the latex of the mango fruit [Mangifera indica, Espada and Rosa (MESPA and MROSA) varieties] and selected monoterpenes on T. urticae. The yield of the MROSA oil was higher (9.22 ± 0.15%). The GC/MS analysis of the oils enabled the identification of 26 constituents. Terpinolene (70.14 ± 0.61%) was the major compound identified in the MESPA oil; β-pinene (38.22 ± 0.80%) was the major constituent of the MROSA oil, followed by terpinolene (29.44 ± 0.29%). The mite was more susceptible to the oils and constituents through fumigation, with no difference between the two varieties. By residual contact, the MROSA oil was 2.7-fold more toxic than the MESPA oil. Terpinolene was the most toxic constituent by fumigation, whereas β-pinene and α-pinene were the most active by residual contact. The selected compounds from M. indica also affected the behavior of the mite, exerting an influence on fecundity, feeding preference and egg-laying preference. The positive control (Azamax®) was more efficient at reducing the fecundity of the mite than the oils, but the MROSA oil was more toxic by fumigation and residual contact. The effects of fumigation and residual contact combined with the change in behavior may be a considerable advantage in the integrated management of T. urticae. For the practical use of these oils as novel acaricides, however, further investigations are needed to evaluate the effects on non-target organisms and the cost-benefit ratio for the formulation of a product to be used on protected crops in the semiarid region of the state of Pernambuco, Brazil.