Abstract

LOERA-BAROCIO, J. Carlos De et al. Susceptibility to insecticides in three mexican populations of the laurel thrips, Gynaikothrips ficorum (Marchal) (Thysanoptera: Phlaeothripidae). Agrociencia [online]. 2011, vol.45, n.1, pp. 61-73. ISSN 1405-3195.

Gynaikothrips ficorum (Marchal) is a pest of the laurel tree in urban zones and insecticides are possibly used for its control, but its initial response to these products is unknown. Therefore susceptibility of various populations of this species was determined (Texcoco, Córdoba and Tlayacapan) to the insecticides permethrin, cypermethrin, diazinón, malathion, methyl oxydemeton, methyl parathion, endosulfán and methomyl. The Texcoco population was used as reference to make comparisons of the response. At 24 h of exposure, the confidence levels of the CL₅₀ of the three populations overlapped in the insecticides cypermethrin, diazinón, malathion and methyl oxydemeton; but they did not overlap in Córdoba and Tlayacapan with Texcoco, for permethrin, methyl parathion, endosulfán and methomyl. For Córdoba and Tlayacapan with cypermethrin, the resistance proportion (RP₅₀) was 0.88 and 0.53'; with diazinón, 0.3 and 0.29'; with malathion 1.04 and 1.02'; with methyl oxydemoton 0.74 and 7.18'; with methyl parathion 8.4 and 4.63'; with endosulfán 1.19 and 0.2', and with methomyl 0.11 and 0.53'. At 95 % mortality, only in Tlayacapan and for endosulfán (RP₉₅=0.03), the fiducial limits did not overlap with the other two populations. The values obtained at 48 h of exposure followed the same tendencies found at 24 h. These response values correspond to a susceptible state and can be used as comparison reference.

Keywords : endosulfán; methomyl; organophosphate; pyrethroids.