Bioactivity of the Cymbopogon citratus (Poaceae) essential oil and its terpenoid constituents on the predatory bug, Podisus nigrispinus (Heteroptera: Pentatomidae)

Made available in DSpace on 2019-10-06T16:34:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-12-01 Podisus nigrispinus Dallas (Heteroptera: Pentatomidae), released in biological control programs, is a predator of Lepidopteran and Coleopteran species. Lemongrass essential oil and its constituents can be toxic to this natural enemy. The major constituents of lemongrass essential oil are neral (31.5%), citral (26.1%), and geranyl acetate (2.27%). Six concentrations of lemongrass essential oil and of its citral and geranyl acetate constituents were applied to the thorax of P. nigrispinus nymphs and adults. The walking and respiratory behavior of the P. nigrispinus third-instar nymphs, treated with citral and geranyl acetate at the LD50 and LD90 doses, were analyzed with video and respirometer. The lemongrass essential oil toxicity increased from first- to fifth-instar P. nigrispinus nymphs. The P. nigrispinus respiration rates (μL de CO2 h−1/insect) with citral and geranyl acetate in the LD50 and LD90 differed. Nymphs exposed to the lemongrass essential oil and its constituents on treated surfaces presented irritability or were repelled. Podisus nigrispinus adults were tolerant to the lemongrass essential oil and its constituents, geranyl acetate and citral. The altered respiratory activity with geranyl acetate and the fact that they were irritated and repelled by citral suggest caution with regard to the use of the lemongrass essential oil and its constituents in integrated pest management incorporating this predator, in order to avoid diminishing its efficiency against the pests. Departamento de Entomologia/BIOAGRO Universidade Federal de Viçosa Departamento de Biologia Geral Universidade Federal de Viçosa Programa de Pós-Graduação em Produção Vegetal Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM) Departamento de Proteção Vegetal Faculdade de Ciências Agronômicas Universidade Estadual Paulista (UNESP), 18610-034, Campus de Botucatu Departamento de Engenharia Florestal Universidade Federal de Viçosa Departamento de Proteção Vegetal Faculdade de Ciências Agronômicas Universidade Estadual Paulista (UNESP), 18610-034, Campus de Botucatu