Banca de DEFESA: MICHELLE MACIEL PEREIRA DE SOUZA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MICHELLE MACIEL PEREIRA DE SOUZA
DATE: 25/02/2025
TIME: 09:00
LOCAL: online
TITLE:

Monitoring the Susceptibility of Phthorimaea absoluta to Azadirachtin.

KEY WORDS:

Phthorimaea absoluta, azadirachtin, susceptibility, Integrated pest management, control failure.

PAGES: 36
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitossanidade
SPECIALTY: Entomologia Agrícola
SUMMARY:

The tomato leaf miner, Phthorimaea absoluta, is a devastating pest for tomato crops (Solanum lycopersicum), causing significant economic losses. The most widely used method for its management is chemical control. Due to its biological characteristics and the widespread application of chemical insecticides, cases of resistance have developed. Azadirachtin, an active compound extracted from neem seeds, has emerged as an important alternative in integrated pest management (IPM) due to its low toxicity to non-target organisms and its effectiveness in controlling P. absoluta. However, information on the susceptibility status of P. absoluta to this molecule is scarce. Therefore, this study aims to monitor the susceptibility of populations of P. absoluta from different regions of Brazil to azadirachtin through bioassays using tomato leaf immersion with the recommended label concentration and concentration-response curves between 2021 and 2023, using leaves treated in azadirachtin solutions in Petri dishes with mortality assessment at 96 hours. The results revealed significant variation in the susceptibility of P. absoluta populations to azadirachtin. The populations from Irecê- BA and João Dourado-BA showed CL50 values of 125.86 mg a.i./L (2023) and 121.3 mg a.i./L (2021), 16.95 mg a.i./L (2023) and 13.75 mg a.i./L (2021), respectively. The resistance ratio varied 7.6 times for the 2021 crop and 3.8 times for the 2023 crop. The lethal concentration for 80% of the population (CL80) varied, with higher values observed in populations from Araguari-MG (271.94 mg a.i./L) and Irecê-BA (246.53 mg a.i./L) in the 2021 crop, and Petrolina-PE (246.53 mg a.i./L) and Irecê-BA (340.40 mg a.i./L) in the 2023 crop. The populations from Irecê-BA and Petrolina-PE showed the highest probabilities of control failure, indicating the need for more robust management strategies in these regions. P. absoluta was shown to be susceptible to azadirachtin, making this molecule a promising tool in the management of P. absoluta. This study reinforces the importance of including this insecticide in IPM programs to reduce selection pressure for resistance and promote more sustainable agricultural practices. Therefore, these findings contribute to the management of this pest insect. 

COMMITTEE MEMBERS:
Presidente - HERBERT ALVARO ABREU DE SIQUEIRA
Interna - ***.662.504-** - VANESKA BARBOSA MONTEIRO - UFRPE
Externa à Instituição - DEBORA BARBOSA DE LIMA MELO - UFPE