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1.
J Econ Entomol ; 106(1): 400-7, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23448057

RESUMEN

The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae) is amajor pest of agriculture worldwide that has proved to be particularly adept at evolving insecticide resistance. Several mechanisms that confer resistance to many insecticide types have been described in M. persicae. We measured the resistance status of nine multilocus genotypes (MLGs) of this aphid species collected in Chile. MLGs were identified using microsatellite markers, and these MLG clonal populations were measured for the presence of modified acetylcholinesterase (MACE), kdr and super kdr mutations, and enhanced carboxyl esterase activity. Toxicological bioassays were used to estimate aphid LC50 when treated with metamidophos (organophosphate), pirimicarb (dimethyl carbamate), cyfluthrin (pyrethroid), and imidacloprid (neonicotinoid). Two MLGs presented >20-fold resistance to pirimicarb, which was associated with the MACE mutation in the heterozygous condition. The kdr mutation was found in only four MLGs in the heterozygous condition and they showed resistance ratios (RR) to cyfluthrin of less than sevenfold. The super kdr mutation was not detected. Enhanced carboxyl esterase activity was predominantly found in the susceptible (S) to first level of resistance (R1) with RR to metamidophos less than eight-fold. Finally, RR to imidacloprid was also less than eight-fold in all MLGs tested. A few MLGs with resistance to pirimicarb were found, while susceptibility to cyfluthrin, metamidophos and imidacloprid was still predominant. A significant positive correlation between imidacloprid tolerance with pirimicarb resistance was detected, as well as between imidacloprid and metamidophos tolerance. With the increase in the use of neonicotinoid insecticides, better rotation of insecticides with different modes of action will be necessary to prevent further development of M. persicae insecticide resistance in Chile.


Asunto(s)
Áfidos/genética , Resistencia a los Insecticidas/genética , Insecticidas , Animales , Carbamatos , Chile , Femenino , Genotipo , Imidazoles , Neonicotinoides , Nitrilos , Nitrocompuestos , Compuestos Organotiofosforados , Piretrinas , Pirimidinas
2.
J Chem Ecol ; 30(12): 2515-25, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15724968

RESUMEN

Five microsatellite loci were used to study the genetic variability and population structure of Sitobion avenae (Hemiptera: Aphididae) on some of its host plants. Individuals were collected in Chile from different cultivated and wild Poaceae. Forty-four multilocus genotypes were found among the 1052 aphids analyzed, of which four represented nearly 90% of the sample. No specialist genotypes were found, although some preferred hosts endowed with chemical defenses, i.e., hydroxamic acids (Hx), while others preferred comparatively undefended hosts. Performances of some predominant and some rare genotypes were evaluated on plants differing in their Hx levels. Significant differences in performance were found among clones, the two most common genotypes showing no differences in performance among all hosts tested, and the rare genotypes showing enhanced performance on the host with highest Hx level. A hypothesis is proposed whereby the appearance of rarer genotypes is in part related to the presence of Hx.


Asunto(s)
Áfidos/fisiología , Células Clonales/fisiología , Interacciones Huésped-Parásitos/genética , Animales , Áfidos/genética , Mecanismos de Defensa , Variación Genética , Genotipo , Interacciones Huésped-Parásitos/fisiología , Repeticiones de Microsatélite , Reacción en Cadena de la Polimerasa , Especificidad de la Especie
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