DIFFERENTIAL PATTERNS OF INSECTICIDE RESISTANCE IN EGGS AND FIRST INSTARS OF TRIATOMA INFESTANS (HEMIPTERA: REDUVIIDAE) FROM ARGENTINA AND BOLIVIA

ARIEL CEFERINO TOLOZA, MÓNICA GERMANO, GASTÓN MOUGABURE CUETO, CLAUDIA VASSENA, EDUARDO ZERBA AND MARÍA INÉS PICOLLO.

JOURNAL OF MEDICAL ENTOMOLOGY

Año: 2008 vol. 45 p. 421 - 426

0022-2585

ABSTRACT. Previous work at our laboratory has indicated high resistance levels to deltamethrin correlated with failures of chemical control in the field of populations in northern Argentina and southern Bolivia. The aim of the present work was to study the resistance patterns in eggs and first instars of T.infestans populations from Argentina and Bolivia. At the egg stage a population from Salvador Mazza, Argentina, showed the highest resistance ratio to deltamethrin and lambda-cyhalothrin, and was susceptible to fipronil and fenitrothion. The population from Mataral, Bolivia, showed very low resistance ratios to deltamethrin and lambda-cyhalothrin and was susceptible to fipronil and fenitrothion. The Sucre population was susceptible to deltamethrin and fenitrothion, and showed very low resistant ratios to lambda-cyhalothrin and fipronil; and the Yacuiba population was susceptible to deltamethrin. At the first instar, Salvador Mazza population was susceptible to fipronil while Mataral and Sucre populations were susceptible to fenitrothion, and showed very low resistance ratios to lambda-cyhalothrin but high resistance to fipronil. The Salvador Mazza population was resistant to deltamethrin at the larval stage. Remarkable differences were found in the resistance profile to fipronil in first instars and eggs from Sucre and Mataral. These indicated that the expression of insecticide resistance in eggs varies between populations, and that the pyrethroid resistance diagnosed in T.infestans first instars is not indicative of resistance in the egg stage.