Acute toxicity and esterase response to carbaryl exposure in two different populations of amphipods Hyalella curvispina.

During the last years, a carbaryl insecticide was extensively applied in the valley of Río Negro and Neuquén, North Patagonia Argentina, to manage codling moths (Cydia pomonella), the main pest of pear and apple trees. In this study carbaryl susceptibility and B-esterase activity from both insecticide-exposed and non-exposed field populations of amphipods Hyalella curvispina were studied. Two subpopulations, one susceptible to carbaryl (LC=213±7.

Acute toxicity and biochemical effects of azinphos methyl in the amphipod Hyalella curvispina.

We evaluated the acute toxicity and biochemical effects of the organophosphorus pesticide azinphos methyl (AM) in the amphipod Hyalella curvispina that inhabits ponds and irrigation channels of an intensive fruit-producing region in Rio Negro and Neuquén valley, North Patagonia, Argentina. The analysis by nonlinear regression of data from the 96 h-acute toxicity tests indicated the coexistence of two subpopulations of H. curvispina with different susceptibilities to AM.

Evolution of insecticide resistance in non-target black flies (Diptera: Simuliidae) from Argentina.

Black flies, a non-target species of the insecticides used in fruit production, represent a severe medical and veterinary problem. Large increases in the level of resistance to the pyrethroids fenvalerate (more than 355-fold) and deltamethrin (162-fold) and a small increase in resistance to the organophosphate azinphos methyl (2-fold) were observed between 1996-2008 in black fly larvae under insecticide pressure. Eventually, no change or a slight variation in insecticide resistance was followed by a subsequent increase in resistance.

Biomarkers of effect in toads and frogs.

Amphibians are good bioindicators of environmental pollution due to their susceptibility to chemicals during their freshwater cycles. The effects of environmental pollution, together with changes in human activity and climate, have contributed to the reduction in the amphibian population over recent decades. However, toxicological research on amphibians has been rather scarce compared with that on other vertebrates.