An alternative to reduce the use of the synthetic insecticide against the maize weevil Sitophilus zeamais through the synergistic action of Pimenta racemosa and Citrus sinensis essential oils with chlorpyrifos

BRITO, V.D.; ACHIMÓN, F.; PIZZOLITTO, R; RAMÍREZ SÁNCHEZ AGRIPINA; GÓMEZ TORRES ELISA; ZYGADLO, J.A.; ZUNINO, M.P.

JOURNAL OF PEST SCIENCE

SPRINGER HEIDELBERG

Lugar: HEIDELBERG; Año: 2020

1612-4758

Sitophilus zeamais attacks stored corn kernels and its control is traditionally carried out using synthetic pesticides. The frequent use of these compounds leads to environmental and health damage and to the development of resistant insect populations. Essential oils (EOs) represent an alternative to conventional pesticides for pest control. The objective of the present study was to evaluate the effect of the combination of EOs with chlorpyrifos against S. zeamais in order to reduce the applied dose of the synthetic insecticide. The most active EOs against S. zeamais were Rosmarinus officinalis, Pimenta racemosa var. ozua and Citrus sinensis. On the other hand, the binary mixtures of EOs showed higher fumigant activity than the individual EOs, being the most active mixtures (1:1 v/v) P. racemosa-R. officinalis, P. racemosa-C. sinensis and R. officinalis-C. sinensis. The combinatory index (CI) values of the binary mixtures showed synergism. All EOs reported repellency against S. zeamais at the tested doses, and the binary combinations of EOs were more repellent than the individual EOs. The P. racemosa-C. sinensis-chlorpyrifos (8:8:1 v/v) combination decreased its LC95 compared to the respective binary mixtures of EOs, showing synergistic effect. In addition, this combination did not show phytotoxicity on maize grains. The binary mixture P. racemosa-C. sinensis repels S. zeamais and, in combination with chlorpyrifos synergizes the effect of the synthetic pesticide without affecting the germination of the maize grains. The use of the mixture P. racemosa-C. sinensis-chlorpyrifos decreases the amount of synthetic insecticide applied, being an interesting alternative for the control of the maize weevil, S. zeamais.