Banca de DEFESA: HAIKA VICTÓRIA SALES MOREIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : HAIKA VICTÓRIA SALES MOREIRA
DATE: 24/02/2026
TIME: 08:30
LOCAL: Google Meet - defesa fechada
TITLE:

Sustainable Biological Control Strategies for Aedes aegypti Based on Metarhizium anisopliae: Association with Coconut Oil, Development of Polymeric Formulations, and Ecotoxicological Evaluation in an Aquatic Environment

KEY WORDS:

Entomopathogenic fungi, Aedes aegypti, coconut oil, CMC, HPMC, Aquatic ecotoxicology

PAGES: 107
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SUMMARY:

New strategies for the control of Aedes aegypti are essential, and the use of entomopathogenic fungi (EPF) associated with other compounds, such as coconut oil and biopolymers, has been explored to enhance virulence, stability, and ease of application. However, it is crucial to assess the toxicity of these formulations to non-target aquatic organisms. The aim of this research was to develop and evaluate the effect of EPF-based formulations against A. aegypti larvae, as well as to assess their ecotoxicity to aquatic organisms. In Chapter I, fungal suspensions at 1×10⁶–10⁷ conidia/mL were combined with coconut oil (0.1%, 0.5%, and 1%; N=30) and tested in vitro and under semi-field conditions (10⁶ conidia/mL + 0.1%; N=60). All fungal concentrations and combinations tested in vitro reduced larval survival compared to the control group (χ²=371.5, df=8, P<0.0001). The association of 1×10⁶ conidia/mL with coconut oil significantly reduced larval survival and showed a synergistic effect (χ²=79.26, df=3, P<0.0001). Metarhizium anisopliae CG 153, with or without oil, also reduced larval survival under semi-field conditions (χ²=384, df=2, P<0.0001). In Chapter II, a biofilm based on carboxymethylcellulose (CMC) and hydroxypropyl methylcellulose (HPMC) was developed. Its compatibility with colony-forming units (CFU) and colony radial growth (CRG) was evaluated, and physicochemical characterization was performed through conformation tests and Scanning Electron Microscopy. The polymeric biofilms were tested against A. aegypti larvae (N=60) in vitro and under semi-field conditions. Physicochemical analyses revealed greenish polymeric biofilms with pH approximately 7, 5 cm in diameter, 0.01 mm thickness, and weighing 0.4 g. Intact conidia were observed under microscopy. HPMC was compatible with M. anisopliae CG 153 (P=0.3696), whereas CMC was incompatible (P<0.0001) in terms of CFU counts. Small differences were observed on days 13 and 14 in CRG for the HPMC group (P=0.0104 and P=0.0062) and CMC group (P=0.0338 and P=0.0338), respectively, compared to the control. Both CMC (χ²=665.4, df=3, P=0.1110) and HPMC biofilms (χ²=501.1, df=3, P<0.0001) showed larvicidal activity. The median survival time (ST₅₀) of larvae treated with CMC control, CMC + CG 153, HPMC, and HPMC + CG 153 biofilms was 4, 3, 1, and 1 day, respectively. The ST₅₀ could not be determined for the untreated control group. Under semi-field conditions, all biofilms exhibited larvicidal activity (χ²=700.4, df=5, P<0.0001); however, the HPMC biofilm with M. anisopliae CG 153 reduced larval survival to 1 day, similarly to CMC control and CMC + CG 153 treatments. In Chapter III, the ecotoxicity of EPF and biopolymers was evaluated in Danio rerio embryos (N=72) and Daphnia magna neonates (N=24). Survival was high in groups exposed to M. anisopliae CG 153 (χ²=5.027; df=6; P=0.4126) and Beauveria bassiana LCMS21 (χ²=11.40; df=5; P=0.0440). CMC reduced the survival of D. rerio exposed to different concentrations (χ²=22.26; df=5; P=0.0005) to values between 61.11% and 76.38%. In contrast, HPMC (χ²=6.2666; P=0.2812) and PVA (χ²=2.213; df=5; P=0.8190) did not significantly affect survival compared to the control. The results demonstrate that the developed formulations and their association with coconut oil are promising strategies to enable the field use of M. anisopliae in the control of A. aegypti. Furthermore, they confirm that the formulations developed in this thesis are safe for aquatic non-target organisms.

COMMITTEE MEMBERS:
Presidente - 2860277 - ISABELE DA COSTA ANGELO
Interna - 2221855 - PATRICIA SILVA GOLO
Interno - 1296670 - WENDELL MARCELO DE SOUZA PERINOTTO
Interna - 1700427 - YARA PELUSO CID
Externa à Instituição - MARIANA GUEDES CAMARGO - UV
Externo à Instituição - GABRIEL MOURA MASCARIN
Externo à Instituição - JOSÉ HENRIQUE VALLIM - EMBRAPA