Effect of toxicity in Folsomia candida by the use of fungicide and insecticide in subtropical soil

Pesticides are widely used for control and prevention against agricultural pests and diseases. The use of these products can negatively affect non-target organisms with important role in soil such as springtails. The present study aimed to evaluate the toxicity of two commercial formulations of pesticides on soil fauna using the springtail Folsomia candida. A natural soil classified as Inceptisol, characteristic of the western region of the Santa Catarina State, was used. The treatments in both tests consisted of six concentrations of the fungicide Comet® (a.i. pyraclostrobin) (0.35; 0.70; 1.40; 2.10; 2.80 and 4.00 mg kg-1 of soil) and of the fungicide + insecticide Standak®Top (a.i. pyraclostrobin + thiophanate-methyl + fipronil) (0.20; 0.60; 1.20; 1.80; 2.40 and 3.00 mg kg-1 soil), plus the control treatment. Acute and chronic tests were carried out following ISO guidelines. Both products proved to be toxic to the evaluated species. Lethality effects were observed in relation to the control of the organisms exposed to low concentrations of the fungicide (0.35 mg kg-1 soil); while for the fungicide + insecticide formulation, lethality was observed at higher concentrations, from 2.40 mg kg-1 soil (LC50 > 3.00 mg kg-1 soil). The reproductive rate was affected only in organisms exposed to the fungicide, with a reduction in the number of juveniles at concentration from 4.00 mg kg-1 soil, with EC20 of 3.38 mg kg-1 soil (2.79–3.96). The results indicate that springtails are sensitive to the tested products, especially to the fungicide that contains the highest concentration of pyraclostrobin in the composition.