Banca de QUALIFICAÇÃO: TEOFILO PAULO LANGA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : TEOFILO PAULO LANGA
DATE: 25/02/2026
TIME: 09:00
LOCAL: Auditorio do CEAGRI II
TITLE:

Resistance monitoring of Phthorimaea absoluta to spinetoram, its characterization and implications for resistance management

KEY WORDS:

Monitoring; Phthorimaea absoluta; spinetoram; insecticide resistance; autosomal inheritance; resistance management

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

Background: Phthorimaea absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) is considered one of the main pests of tomato crops, standing out for its high capacity to develop resistance to insecticides. Spinosyns, especially spinetoram, have been widely employed in the management of this species due to their high efficacy and selectivity. In this context, the present study aimed to select a field-derived population of P. absoluta resistant to spinetoram, in order to characterize the genetic and biochemical foundations involved, as well as to identify possible associated cross-resistance patterns.
Results: A high level of resistance (1144.68-fold) was observed in the Paty-Sel population, with reciprocal F₁ and F₁′ crosses indicating autosomal inheritance. Dominance degrees (D), ranging from –0.43 to –0.57, characterized the resistance as incompletely recessive, and the direct inheritance test pointed to the involvement of a single gene. Synergism ratios for LIN-Sus were 1.98, 1.25, and 1.7-fold, whereas for PTY-Sel they reached 7.59, 8.78, and 4.9-fold after exposure to the synergists PBO, DEM, and DEF, respectively. Resistance ratios of 682.70, 2.59, and 2.58-fold were observed for spinosad, indoxacarb, and tolfenpyrad, as well as negative cross-resistance for cyclaniliprole (0.51) and isocycloseram (0.50). The lowest concentration capable of causing total mortality of heterozygotes was 15 mg/L of spinetoram, making the resistance functionally recessive.
Conclusion: It is concluded that continuous selection of P. absoluta with spinetoram promotes rapid evolution of resistance, presenting autosomal, monogenic inheritance and incomplete dominance. Bioassays indicate limited contribution of metabolic mechanisms, suggesting target-site alterations as the main resistance mechanism. The high cross-resistance to spinosad reinforces this interpretation, while the negative cross-resistance to cyclaniliprole and isocycloseram indicates promising alternatives for sustainable management under high chemical pressure

 

COMMITTEE MEMBERS:
Presidente - HERBERT ALVARO ABREU DE SIQUEIRA
Interno - MANOEL GUEDES CORREA GONDIM JUNIOR
Externa à Instituição - VANESKA BARBOSA MONTEIRO - UFRPE