Evaluaci?3n de la susceptibilidad de Aphis craccivora Koch (Hemiptera: Aphididae) a pirimicarb en condiciones de laboratorio

摘要

The susceptibility of cowpea aphid, Aphis craccivora (Koch) to active ingredient pirimicarb was evaluated under conditions of 26 ?± 2 ?°C, 60 ?± 15% RH and a photoperiod of 12:12 h (L: D). Aphids were collected in two different locations of the Regi?3n de Tarapac??, Chile, one with high applications of insecticides (Parca) and other without application (Noaza). Insects were exposed to different concentrations of pirimicarb applied with a Potter tower, determining that the high level of insecticide applications Pirimor?? (a.i. pirimicarb) for controlling aphids in Parca, has generated a loss of susceptibility to this product due the low per-centage of mortality (between 40.40 ?± 4.70%o and42.60 ?± 4.35%) reached when the minimumdose recommended by manufacturer was applied (750.0 mgL-1) compared to the susceptiblepopulation which reached to mortalities ranging between 77.40 ?± 3.31% and 87.30 ?± 3.35%. The probit analysis showed no significant differences between the LC50 of two populations studied ENT#091;Parca: LC50 = 862.40 mg L-1 (508.85-1017.70); Noaza: LC50 = 519.14 mgL-1 (369.07-615.06)ENT#093;, while the resistance ratio of 1.7X, showed that aphids population from Parca, have not yet developed resistance to pirimicarb.