Pesticide use generates wastewaters from its handling and from washing of spraying equipment, bringing concern about punctual discharge. Biobeds are biopurification systems for pesticide residues disposal, representing safe alternatives to avoid soil contamination. Peat that composes the original biomixture is not available all around Brazil. The aim of this work was to evaluate the efficiency of two alternative, accessible biomixtures, replacing peat, for treating phosmet (organophosphate insecticide) residues in biobeds and reducing its ecotoxicological effects. We hypothesized that the new biomixtures with pine litter (PB) or vermicompost (VB) could show the same degradation and detoxification efficiency as the standard biobed’s biomixture (SB) using peat. Small size bioreactors received 35 mg kg⁻¹ of phosmet (Imidan®) in a laboratory-scale experiment. The pesticide degradation was monitored by chemical analysis. The decrease of ecotoxicity was determined by reproduction tests with collembolans (Folsomia candida) and enchytraeids (Enchytraeus crypticus), following ISO guidelines. Degradation curves showed that all biomixtures reached almost complete degradation of phosmet after 90 days. Collembolans were more sensitive than enchytraeid, confirming their usefulness in biomonitoring insecticide degradation. This work showed that both pine litter and vermicompost are potentially substitutes for peat in alternative biomixtures, since they were efficient in degrading the pesticide and reducing its ecotoxicity. Our results contribute for the development of newly, accessible biobeds for south Brazil, bringing the first study reports involving such biobeds capacity to degrade phosmet, which is a commonly used pesticide in this region.

Field and lab trials took place in Crete (July to September 2016), concerning the residual degradation and toxicity of seven active ingredients applied as bait sprays against the olive fruit fly. Highest residues were recorded in olive leaves for dimethoate and phosmet (~ 60 mg/kg) immediately after application (day 1+), while a threefold and fivefold reduction was observed 1 week later, respectively. Residues of pyrethroids were determined at lower levels (< 10 mg/kg) but remained almost stable for a longer period of time. Finally, thiacloprid and spinosad residues were determined at 5.81 and 0.19 mg/kg respectively (day 1+), and rapidly decreased below the LOQ. Highest toxicity against the olive fruit fly was observed just right after the application of dimethoate (100%), a-cypermethrin (80%), and L-cyhalothrin (72.92%). Although the toxicity of dimethoate was significantly reduced 1 week after the application (80%) and then minimized, toxicity of pyrethroids remained almost stable (> 60%) for the first 2 weeks and then decreased to 30–40%, which remained stable up to the end of the study (8 weeks). Concerning phosmet, its toxicity ranged from 35 to 56% for 3 weeks with no significant reduction, while spinosad presented a lower toxicity profile (50% only for 1 week). The benefits of these results in the knowledge of insecticide residues and their toxicity against olive fruit fly can be used for improving olive fruit fly control.