Quinto V

References (4)

Title : Esterase inhibition by synergists in the western flower thrips Frankliniella occidentalis - Lopez-Soler_2011_Pest.Manag.Sci_67_1549
Author(s) : Lopez-Soler N , Cervera A , Quinto V , Abellan J , Bielza P , Martinez-Pardo R , Garcera MD
Ref : Pest Manag Sci , 67 :1549 , 2011
Abstract : BACKGROUND: Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is among the most important crop pests in the south-eastern region of Spain. Its increasing resistance to insecticides constitutes a serious problem, and understanding the mechanisms involved is therefore of great interest. Use of synergists to inhibit the enzymes involved in insecticide detoxification is widely used to determine their responsibility for insecticide resistance. However, they do not always act as intended or expected, and caution must be exercised when interpreting synergist results. RESULTS: Laboratory-selected strains of WFT were used to analyse the effects of the synergists piperonyl butoxide (PBO), S,S,S-tributyl phosphorotrithioate (DEF) and methiocarb on total esterase activity. Significant differences were found, indicating esterase activity inhibition by DEF, a lower effect for methiocarb and a small inhibition of the activity by PBO. Esterase isoenzyme inhibition by these compounds showed a similar result; this assay revealed an extreme sensitivity of Triplet A (resistance-associated esterases) to DEF. In an in vivo assay carried out with these compounds at different incubation times, only DEF caused posterior in vitro esterase activity inhibition, with a maximum effect 1 h after treatment. CONCLUSION: In this work, only DEF shows true synergistic inhibition of WFT esterases.
ESTHER : Lopez-Soler_2011_Pest.Manag.Sci_67_1549
PubMedSearch : Lopez-Soler_2011_Pest.Manag.Sci_67_1549
PubMedID: 21656898

Title : Life-stage variation in insecticide resistance of the western flower thrips (Thysanoptera: Thripidae) - Contreras_2010_J.Econ.Entomol_103_2164
Author(s) : Contreras J , Espinosa PJ , Quinto V , Abellan J , Gravalos C , Fernandez E , Bielza P
Ref : J Econ Entomol , 103 :2164 , 2010
Abstract : The life-stage variations in insecticide resistance of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), to selective insecticides (acrinathrin, formetanate, and methiocarb) were studied using resistant laboratory strains. In each strain, the second-instar larva was less susceptible to the insecticides tested than the adults. The lower the resistance level of the adults, the higher the difference between larva and adult susceptibility: 32-fold to methiocarb, 15.4-fold to formetanate, and 180-fold to acrinathrin in the reference strain. In laboratory-selected resistant strains, these differences were much lower: 5.8-fold to methiocarb, 4.8-fold to formetanate, and 2.0-fold to acrinathrin. In selected strains, higher resistance levels for each insecticide were found, both for larvae and adults, compared with the reference strain. These results show that after insecticide resistance selection in adults, the resistance is carried over to the larvae, but at lower levels.
ESTHER : Contreras_2010_J.Econ.Entomol_103_2164
PubMedSearch : Contreras_2010_J.Econ.Entomol_103_2164
PubMedID: 21309240

Title : Impact of production system on development of insecticide resistance in Frankliniella occidentalis (Thysanoptera: Thripidae) - Bielza_2008_J.Econ.Entomol_101_1685
Author(s) : Bielza P , Quinto V , Gravalos C , Fernandez E , Abellan J
Ref : J Econ Entomol , 101 :1685 , 2008
Abstract : The western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), has become one of the most difficult insects to control in the intensive agriculture of southeastern Spain. However, resistance problems are quite different in two neighboring areas, Murcia and Almeria, with distinct production systems. Thirty-six field populations of western flower thrips from sweet pepper crops were collected in two different dates in Murcia and Almeria in 2005 and 2006. Western flower thrips populations collected were exposed to a diagnostic concentration of spinosad, methiocarb, acrinathrin, and formetanate. The results allowed the recognition of higher levels of resistance in Almeria compared with Murcia throughout the growing season. The mortality at the diagnostic concentration for spinosad (120 ppm) in western flower thrips populations ranged from 34 to 81% in Almeria, and from 73 to 100% in Murcia. The mortalities at the diagnostic concentration to acrinathrin (800 ppm) and formetanate (8000 ppm) were 17-31% in Almeria and 77-100% in Murcia, and 14-41% in Almeria and 48-99% in Murcia, respectively, indicating large geographic variations. Toxicity of methiocarb was higher for western flower thrips populations from both areas. However, mortality at the diagnostic concentration of methiocarb (2000 ppm) varied from 56 to 90% in Almeria, and it was from 94 to 100% in Murcia. The impact of production systems and agricultural practices of each area on the development and stability of insecticide resistance is discussed.
ESTHER : Bielza_2008_J.Econ.Entomol_101_1685
PubMedSearch : Bielza_2008_J.Econ.Entomol_101_1685
PubMedID: 18950052

Title : Metabolic mechanisms of insecticide resistance in the western flower thrips, Frankliniella occidentalis (Pergande) - Espinosa_2005_Pest.Manag.Sci_61_1009
Author(s) : Espinosa PJ , Contreras J , Quinto V , Gravalos C , Fernandez E , Bielza P
Ref : Pest Manag Sci , 61 :1009 , 2005
Abstract : The interactions between six insecticides (methiocarb, formetanate, acrinathrin, deltamethrin, methamidophos and endosulfan) and three potential synergists (piperonyl butoxide (PBO), S,S,S-tributyl phosphorotrithioate (DEF) and diethyl maleate (DEM)) were studied by topical exposure in strains selected for resistance to each insecticide, and in a susceptible strain of Frankliniella occidentalis (Pergande). In the susceptible strain PBO produced appreciable synergism only of formetanate, methiocarb and methamidophos. Except for endosulfan, PBO synergized all the insecticides to varying degrees in the resistant strains. A very high level of synergism by PBO was found with acrinathrin, which reduced the resistance level from 3344- to 36-fold. PBO slightly synergized the carbamates formetanate (4.6-fold) and methiocarb (3.3-fold). PBO also produced a high synergism of deltamethrin (12.5-fold) and methamidophos (14.3-fold) and completely restored susceptibility to both insecticides. DEF did not produce synergism with any insecticide in the resistant strains and DEM was slightly synergistic to endosulfan (3-fold). These studies indicate that an enhanced detoxification, mediated by cytochrome P-450 monooxygenases, is the major mechanism imparting resistance to different insecticides in F occidentalis. Implications of different mechanisms in insecticide resistance in F occidentalis are discussed.
ESTHER : Espinosa_2005_Pest.Manag.Sci_61_1009
PubMedSearch : Espinosa_2005_Pest.Manag.Sci_61_1009
PubMedID: 15912569