Banca de QUALIFICAÇÃO: TALIA SILVA RIBEIRO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : TALIA SILVA RIBEIRO
DATE: 14/12/2022
TIME: 09:30
LOCAL: Campus Paulo Freite
TITLE:

EVALUATION OF THE TOXICITY OF THE ESSENTIAL OIL OF THE RESIN OF Protium heptaphyllum ON Sitophilus zeamais FOR APPLICATION IN CORN GRAIN IN STORAGE

KEY WORDS:

amescla, ecological control, stored grain, vegetable insecticides.

PAGES: 36
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUMMARY:

The maize weevil (Sitophilus zeamais) is one of the main pests of stored grains and causes quantitative and qualitative damage. Its control is carried out with synthetic insecticides, fumigants and protectors. Highly toxic products, which leave residues and encourage the emergence of resistant populations. So, in order to move towards an agroecological production and reduce the use of these chemicals, they have been testing new ways of protecting food, with alternative, accessible and adequate control methods using plant by-products with insecticidal action. The present study aims to evaluate the efficiency of the essential oil of P. heptaphyllum resin in the control of Sitophilus zeamais in stored corn grains, investigating its insecticide potential and interference in the germination process. The collection of Protium heptaphyllum resin was carried out in the Parque Nacional do Descobrimento, in the municipality of Prado - BA and the essential oil was extracted by hydrodistillation in a Clevenger type apparatus. To identify the chemical constituents, gas chromatography associated with mass spectrometry (GC-MS) of the essential oil was performed. The non-sexed insects used were obtained from infected corn from the local market in the extreme south of Bahia and reared in the laboratory under conditions of T: 25 ± 3°C and RH: 65 ± 5% and photophase: 12 h. In the initial tests (stage I) evaluated the mortality rate of insects against different concentrations of essential oil in exposure via contact after 12, 24, 48, 72 and 96 h and by fumigation in 48 h, to determine the lethal concentrations (LC50 ), dosages from 62.5 to 2500 ppm were tested. In step II, corn seeds of the creole variety will be coated with lethal concentrations of the essential oil determined in the bioassays. Afterwards, they were stored for four months and five evaluations were carried out within thirty days of the following parameters: loss of grain mass, number of grains infested by insects, total number of insects, water content of seeds and germination test. The collected data will undergo an exploratory analysis for the analysis of homogeneity and normality of variance of the treatments, being applied to ANOVA, parametric and/or non-parametric. For multiple comparisons, the Kruskal Test - Wallis, SNK and Wilcoxon will be used. Mortality will be determined by Probit analysis, depending on storage time. GC-MS analysis revealed that the essential oil of P. heptaphyllum resin contains 62.26% of Limonene, a terpene with known insecticidal activity. In preliminary results, the essential oil showed low toxicity for contact and fumigation tests against the insect pest S. zeamais for the tested dosages, and it was not possible to identify the CL50. Thus, we can infer the need to repeat the bioassays with other dosages to determine the adequate concentration to control corn weevil in stored corn grains.

COMMITTEE MEMBERS:
Externa ao Programa - 1156996 - LIVIA SANTOS LIMA LEMOS - nullPresidente - 1906490 - LUANNA CHACARA PIRES
Interno - 1322722 - SEBASTIAO RODRIGO FERREIRA
Externa ao Programa - 1149467 - TAINA SORAIA MULLER - null