Banca de QUALIFICAÇÃO: FRANCISCO ANTONIO MABSON HENRIQUE LOPES

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : FRANCISCO ANTONIO MABSON HENRIQUE LOPES
DATE: 30/07/2025
TIME: 14:00
LOCAL: Auditório do Departamento de Química
TITLE:

Study of Formulations of Binary Mixtures Based on Essential Oils and Fixed Oils with Acaricidal and Insecticidal Properties against Tetranychus urticae and Plutella xylostella

KEY WORDS:

Essential oils. Fixed oils. Synergism. Tetranychus urticae. Plutella xylostella.

PAGES: 140
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Química dos Produtos Naturais
SUMMARY:

Agricultural pests such as Tetranychus urticae and Plutella xylostella cause millions of reais in losses to farmers. These pests are controlled through the application of synthetic insecticides, but their indiscriminate use has caused serious environmental impacts and led to the development of pest resistance. As an alternative, the objective of this study was to evaluate the insecticidal and acaricidal efficacy of botanical insecticides based on essential oils from Lippia grata and Melaleuca leucadendra and fixed oils extracted from agroindustrial residues of Spondias mombin (cajá) and Malpighia emarginata (acerola), focusing on the development of formulations from binary mixtures. The oils were analyzed using spectrometric techniques, and acaricidal and insecticidal tests, at different stages of pest development, were conducted in the laboratory and in the field. The chemical composition analyses of the oils revealed distinct profiles, with a predominance of carvacrol (53.19%) in L. grata and (E)-nerolidol (96.13%) in M. leucadendra, while the fixed oils were rich in fatty acids, such as palmitic (26.47% and 21.60%), linoleic (28.85% and 21.54%), and oleic (34.78% and 10.16%), for Malpighia emarginata and Spondias mombin, respectively. All oils demonstrated toxicity to the pests, with emphasis on the high ovicidal toxicity observed against T. urticae. The evaluation of the binary mixtures revealed synergistic interactions, mainly in the combinations of M. leucadendra oil with both fixed oils against T. urticae, resulting in LC50 values significantly lower than those of the isolated oils. Acetylcholinesterase (AChE) inhibition assays indicated neurotoxicity as the main mechanism of action of essential oils, complemented by the physical action of fixed oils. The robustness of the formulations was confirmed in semi-field experiments, where the synergistic mixtures achieved 100% mortality of T. urticae, surpassing the positive control (Azamax®). The results obtained here demonstrate that the combination of essential oils and fixed oils evaluated is a promising and sustainable strategy for the development of a new botanical insecticide.

COMMITTEE MEMBERS:
Interno - CLAUDIO AUGUSTO GOMES DA CAMARA
Interno - JOAO RUFINO DE FREITAS FILHO
Interno - MARCILIO MARTINS DE MORAES
Externo ao Programa - 2002989 - ANDRE AUGUSTO PIMENTEL LIESEN NASCIMENTO - UFRPEExterna ao Programa - ***.132.244-** - CAROLINA ALVES DE ARAUJO - UFRPE