Banca de DEFESA: TALIA SILVA RIBEIRO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : TALIA SILVA RIBEIRO
DATE: 15/12/2023
TIME: 08:00
LOCAL: webconferencia: link: https://meet.google.com/mfh-zotf-hdh
TITLE:

Assessment of the toxicity of essential oils on Sitophilus zeamais for application in stored corn grains

KEY WORDS:

Ecological Control, Stored Grains, Corn weevil, Botanical insecticides, Storage pests

PAGES: 65
BIG AREA: Ciências Agrárias
AREA: Engenharia Agrícola
SUBÁREA: Engenharia de Processamento de Produtos Agrícolas
SPECIALTY: Armazenamento de Produtos Agrícolas
SUMMARY:

The corn weevil (Sitophilus zeamais) is one of the main pests of stored grains and causes quantitative and qualitative losses, found mainly in hot and humid regions around the world. Control of this insect is carried out with conventional insecticides, which cause undesirable effects with the presence of dangerous levels of residues and the selection of resistant populations. So, in order to transition to agroecological production, they have been testing new ways of protecting food, with alternative, accessible and appropriate control methods using botanical by-products with insecticidal action. The present study is a pioneer in the identity territory and aims to evaluate the insecticidal potential of essential oils from species native to the Atlantic Forest and commercial essential oils for the control of S. zeamais in stored corn grains. In chapter I, an integrative review was carried out on the main chemical components of essential oils that have insecticidal action on corn weevils. The search was carried out in the following databases: Scopus, PubMed, Web of Science, Virtual Health Library, Scielo and Sciencedirect and Google Scholar. The search found 754 articles and 117 were selected. For the other chapters, the essential oil was obtained by two methods, acquired in local stores and also from the collection of botanical material in the National Discovery Park, municipality of Prado – BA and the oil extracted by hydrodistillation in a Clevenger-type device. To identify the chemical constituents, gas chromatography associated with mass spectrometry (GC-MS) of the essential oil was carried out. The unsexed insects used were obtained from infected corn from local stores in the Far South of Bahia and raised in the laboratory under conditions of T: 25 ± 3°C and RH: 65 ± 5%. Chapters I and II were the bioassays to evaluate toxicity by direct contact and fumigants, in which the mortality rate of 20 adult insects per experimental unit was evaluated in different concentrations of the essential oil from the resin of Protium heptaphyllum, Piper macedoi, Mentha piperita , Maleleuca alternifolia, Rosmarinus officinalis, Cymbopogon nardus and Schinus terebinthifolius Raddi (leaf and seed), exposed via contact after 12, 24, 48, 72 and 96 h and the resin of Protium heptaphyllum, the seed of Schinus terebinthifolius Raddi and Rosmarinus officinalis by fumigation at 12, 24 and 48 hours, with the aim of determining lethal concentrations (LC50 and LC 90). The collected data underwent an exploratory analysis to analyze the homogeneity and normality of variance of the treatments, using ANOVA, parametric and/or non-parametric. For multiple comparisons, the Kruskal - Wallis, SNK and Wilcoxon test will be used. Mortality will be determined through Probit analysis, depending on storage time. GC-MS analysis revealed that the essential oil from P. heptaphyllum resin contains 62.26% Limonene, a monoterpene with known insecticidal activity. In preliminary results from Stage I, the essential oil showed low toxicity for contact and fumigation tests against the insect pest S. zeamais for the dosages tested, and it was not possible to identify the LC50. Therefore, there is a need to repeat bioassays with higher dosages to determine the appropriate concentration to control corn weevils in stored corn grains.

COMMITTEE MEMBERS:
Presidente - 1906490 - LUANNA CHACARA PIRES
Interna - 1716815 - GISELE LOPES DE OLIVEIRA
Interna - 1197643 - MARCIA NUNES BANDEIRA RONER
Interno - 1322722 - SEBASTIAO RODRIGO FERREIRA
Externa ao Programa - 1156996 - LIVIA SANTOS LIMA LEMOS - UFSBExterna ao Programa - 1149467 - TAINA SORAIA MULLER - UFSB