The ecological and economic contributions of pollinator bees to agricultural production have been threatened by the inappropriate and excessive use of pesticides. These pesticides are often applied in areas with ecological peculiarities (e.g., the Neotropical savannah-like region termed as Cerrado) that were not considered during the product development. Here, we conducted field experiments with melon (i.e., Cucumis melo L.) plants cultivated under Brazilian Cerrado conditions and evaluated the impacts of botanical (i.e., neem-based insecticide) and synthetic (i.e., the pyrethroid insecticide deltamethrin and the fungicides thiophanate-methyl and chlorothalonil) pesticides on the flower visitation rates of naturally occurring pollinator bees. Our results revealed that both honey bees (i.e., Apis mellifera L.) and non-Apis bees visited melon flowers and the intensity of bee visitation was moderately correlated with yield parameters (e.g., number of marketable fruits and fruit yield). Pesticide treatments differentially affected bee species. For instance, Plebeia sp. bees were not affected by any pesticide treatment, whereas both A. mellifera and Halictus sp. bees showed reduced visitation intensity after the application of deltamethrin or neem-based insecticides. Fungicide treatment alone did not influence the bee's visitation intensity. Deltamethrin-treated melon fields produced significantly lighter marketable fruits, and the melon yield was significantly lower in melon fields treated with the neem-based insecticide. Thus, our findings with such pollinator bees reinforce the idea that field applications of botanical pesticides may represent as risky as the applications of synthetic compounds, indicating that these alternative products should be submitted to risk assessments comparable to those required for synthetic products.

Thiophanate methyl is a broad-spectrum benzimidazole fungicide extensively applied in pre- and post-harvest, for the control of a wide range of fruit and vegetable pathogens. In the current work, the residue behavior of thiophanate methyl after application on strawberries and an estimation of the consumer dietary exposure was performed. Supervised field trials were conducted in Egypt (Qaluobiya Governorate) as to investigate the residue dynamics and terminal residues at different PHIs of thiophanate methyl and its metabolite carbendazim in strawberries under Egyptian conditions. For the measurement of residues in fruits, a QuEChERS-based protocol coupled with LC–MS/MS was optimized and successfully validated at 0.01 mg kg⁻¹. The half-life (t₁/₂) of thiophanate methyl in strawberries was estimated, and a dietary risk assessment was performed employing both FAO/WHO and EFSA approaches.

The concentration levels of some important pesticides were evaluated in soil samples from different areas of the North of Iran (Golestan province) and to indicate the possible sources and risks of contamination. A multiresidue analytical procedure using the QuEChERS approach was developed to extract and measure 12 pesticide residues from ten different classes in 145 soil samples including agricultural, garden, forestal, and residential areas. The analysis was performed using reversed-phase liquid chromatography equipped with an ESI mass spectrometry instrument by multiple reaction monitoring (MRM) in positive-ion modes. Retention times and occurrence of two conventional transitions were used as identification criteria. Three pesticide residues including malathion, propargite, and butachlor were observed in soil samples. Malathion residue was found in ˃ 51% of soil samples, and its levels in approximately 35% of the cases were more than the residue limit (50 μg kg⁻¹). Propargite residue was observed in 49% of the samples and its levels in 11% of the cases were more than the residue limit. The most frequently observed levels of malathion and propargite were found in forestal and residential areas. The amount of butachlor residue in one of the residential soil samples was at least 10 times more than the residue limit. Some of the pesticides including imidacloprid, cyproconazole, diazinon, and chlorpyrifos displayed residue levels below 50 μg kg⁻¹. The other pesticides, namely carbaryl, thiophanate-methyl, fenpropathrin, krezoxim-methyl, and pinoxaden, were not detected in any soil samples. These findings might be useful for implementing programs to monitor the presence of pesticides in soils and the related crops, to carry out more precise risk assessment studies.

Residue analysis to detect thiophanate-methyl and its primary metabolite (carbendazim) during oyster mushroom (Pleurotus ostreatus var. florida) cultivation was done for two consecutive years 2017 and 2018. Wheat straw substrate was chemically treated with different treatments of thiophate-methyl, viz, thiophanate-methyl 30 ppm + formalin 500 ppm (T1), thiophanate-methyl 40 ppm + formalin 500 ppm (T2), thiophanate-methyl 50 ppm + formalin 500 ppm (T3), thiophanate-methyl 60 ppm + formalin 500 ppm (T4), and formalin 500 ppm (T5 as control and recommended concentration), and utilized for cultivation of oyster mushroom. Treatments T3 and T4 exhibited significant difference in pH levels during both the trials. Minimum spawn run, pinhead formation, and fruit body formation time were recorded in treatments T3 and T4. Significantly higher biological efficiency (%) was recorded in treatments T3 and T4 as compared with all other treatments. No incidence of competitor molds was recorded in T3 and T4. Pesticide residue analysis for detection of thiophanate-methyl and its metabolite (carbendazim) was done in the fruit body produced in T3 and T4 treatments using liquid chromatography with tandem mass spectrometry method. No residue of thiophanate-methyl and carbendazim was detected at 50 ppm concentration of thiophanate-methyl during both the trials. However, in trial II, residue of carbendazim (5.39 μg/kg) was detected at 60 ppm. Based on the findings of the trials I and II, T3 (thiophanate-methyl 50 ppm + formalin 500 ppm) may be utilized for substrate sterilization for oyster mushroom cultivation and Pleurotus ostreatus var. florida could be recognized as microorganism which could play a role in degradation of thiophanate-methyl.